The Best Raspberry Rhubarb Buckle Recipe: A Sweet & Tart Spring Dessert Sensation

Springtime brings with it a bounty of fresh produce, and for many home bakers, nothing signals the start of the season quite like the arrival of vibrant rhubarb stalks. This often-underestimated vegetable, with its distinct tartness, is a true culinary gem, especially when paired with sweet, juicy fruits. Our Raspberry Rhubarb Buckle recipe is designed to celebrate this fleeting ingredient, transforming it into a moist, flavorful cake that’s perfect for any occasion, from a casual brunch to an elegant dessert.

If you’re anything like me, the moment you spot those gorgeous pink and green stalks at your local market, you know it’s time to get baking. Rhubarb holds a special place in my heart, evoking floods of fond childhood memories of pies and crumbles from my grandmother’s kitchen. This buckle recipe captures that nostalgic comfort while offering a sophisticated blend of flavors that will delight your taste buds.

A “buckle” is a delightful type of fruit cake, known for its moist crumb and a generous, crumbly streusel topping. It earns its charming name from the way the cake “buckles” or sinks slightly around the fruit as it bakes, creating an inviting, rustic appearance. This particular recipe combines the tartness of rhubarb with the sweet-tart burst of raspberries, creating a harmonious balance that is simply irresistible. It’s a beautifully simple yet profoundly satisfying dessert that truly highlights the best of spring and early summer produce.

For quick access to the full recipe card with precise ingredient measurements and step-by-step instructions, please use the JUMP TO RECIPE button at the top of the post, or simply scroll down to the bottom.

Why This Raspberry Rhubarb Buckle is a Must-Try

This Raspberry Rhubarb Buckle is more than just a dessert; it’s a celebration of seasonal flavors and simple, comforting baking. The combination of rhubarb’s unique tang and raspberries’ vibrant sweetness creates a truly dynamic flavor profile that stands out. Unlike a dense pie or a simple crumble, a buckle offers a cake-like base that is incredibly tender and moist, allowing the fruit to truly shine without being overwhelmed. The buttery streusel topping adds a delightful contrast in texture, providing a golden, crisp crunch with every bite.

It’s also an incredibly versatile recipe. While raspberry and rhubarb are a classic pairing, the underlying cake structure is robust enough to accommodate a variety of fruits. This makes it a fantastic go-to recipe for utilizing whatever fresh produce is abundant in your garden or local market throughout the year. Beyond its deliciousness, this buckle is surprisingly easy to make, even for novice bakers. With clear instructions and readily available ingredients, you’ll be able to whip up this show-stopping dessert with confidence.

Whether you’re serving it warm with a scoop of vanilla ice cream or enjoying it at room temperature with a dollop of whipped cream, this Raspberry Rhubarb Buckle promises a memorable culinary experience. It’s the kind of dessert that gathers people around the table, fostering warmth and happy conversations. So, let’s dive into the details of creating this irresistible spring treat!

Essential Ingredients for the Perfect Raspberry Rhubarb Buckle

One of the beauties of this Raspberry Rhubarb Buckle recipe is that, aside from the star ingredient (rhubarb!), most of the components are likely already staples in your pantry. I find myself always stocked with these essentials, making it incredibly easy to jump into baking the moment fresh rhubarb makes its seasonal debut.

Let’s take a closer look at the key ingredients and why they are important:

• Fresh Rhubarb: This is the heart of our buckle. Look for firm, crisp stalks, typically reddish-pink to green. While fresh is ideal for its vibrant flavor and texture, I’m happy to report that this recipe also works exceptionally well with frozen rhubarb. If you’re using frozen, there’s no need to thaw it beforehand; simply chop it if necessary and toss it with the sugar as directed.
• Fresh Raspberries: These berries add a beautiful burst of color, a delightful tartness, and a touch of sweetness that complements the rhubarb perfectly. Choose plump, firm raspberries. Like rhubarb, frozen raspberries can also be used here.
• Unsalted Butter (softened): Used in both the streusel topping and the cake batter, butter provides richness, flavor, and contributes to the tender crumb of the cake. Ensuring it’s softened for the cake batter helps achieve a light and airy texture when creamed with sugar.
• Granulated Sugar: Sweetens both the fruit mixture (for macerating) and the cake batter. It balances the tartness of the rhubarb and raspberries.
• Brown Sugar (packed): Exclusively for the streusel, brown sugar adds a deeper, molasses-like flavor and helps create that desirable chewy, crunchy texture in the topping.
• All-Purpose Flour: The structural foundation of both the streusel and the cake.
• Cinnamon: A warm spice that enhances the overall flavor profile of the streusel, adding a comforting aroma.
• Large Egg: Acts as a binder in the cake batter, contributing to its structure and moisture.
• Lemon Zest: A secret weapon for brightness! Lemon zest elevates the fruit flavors and adds a wonderfully fresh aroma to the cake without making it taste distinctly lemony.
• Baking Powder: Our primary leavening agent, ensuring the cake rises beautifully and achieves a light, tender crumb.
• Kosher Salt: A pinch of salt is crucial for balancing the sweetness and enhancing all the other flavors in the cake.
• Buttermilk: This acidic dairy product reacts with the baking powder, promoting a tender crumb and a slight tang that complements the fruit. If you don’t have buttermilk, you can make a substitute by adding 1 tablespoon of white vinegar or lemon juice to a measuring cup and filling the rest with regular milk to make ½ cup. Let it sit for 5-10 minutes until it slightly curdles. (Note: The original text specifies “not oat milk” for dairy-free substitutions; this implies it’s suitable for regular buttermilk replacement too.)

This wonderful buckle truly is a perfect basic cake recipe that provides an excellent base. With just a few adjustments, you can fold almost any fruit into this batter and achieve a fantastic result. It’s a versatile blueprint for countless delicious desserts, but for now, let’s stick to the glorious raspberry and rhubarb combination.

Method: Step-by-Step Guide to Baking Your Raspberry Rhubarb Buckle

Creating this Raspberry Rhubarb Buckle is a straightforward process, but a few key steps ensure a perfect outcome. Follow these instructions carefully, and you’ll be rewarded with a moist cake topped with a crispy, sweet streusel.

1. Prepare the Streusel Topping

I always begin by making the crumbly topping first. In a medium bowl, combine the softened unsalted butter, packed brown sugar, granulated sugar, all-purpose flour, and cinnamon. Use your fingertips or a pastry blender to work the ingredients together until a coarse, crumbly mixture forms. The mixture should resemble wet sand with some larger pea-sized clumps. Once combined, cover the bowl and chill it in the refrigerator. This crucial step helps the butter in the topping hold its structure better in the hot oven, resulting in a crisper, more defined streusel that won’t melt too quickly into the cake batter.

2. Macerate the Fruit

Next, prepare your fresh (or frozen) rhubarb and raspberries. Chop the rhubarb into 1-inch pieces, ensuring they are relatively uniform for even cooking. Place the chopped rhubarb and fresh raspberries in a separate bowl. Sprinkle ¼ cup of granulated sugar over the fruit and gently toss to coat. Allow the fruit to macerate while you prepare the cake batter. Macerating means letting the fruit sit with sugar, which draws out some of its natural juices. This intensifies the fruit’s flavor and helps prevent the finished cake from becoming too soggy by releasing excess liquid before baking.

3. Prepare the Cake Batter

Preheat your oven to 350°F (175°C). Line an 8×8 inch square baking tin with nonstick spray and parchment paper. It’s important to leave some parchment paper hanging over the edges; these “sling” handles will make it much easier to lift the baked buckle out of the pan later. In the bowl of a stand mixer fitted with the paddle attachment, or with a hand mixer, cream together the remaining ¾ cup granulated sugar and ¼ cup unsalted butter until the mixture is light, fluffy, and pale in color. This process incorporates air, contributing to the cake’s tender texture.

Add the large egg and the zest of one lemon to the creamed mixture. Beat until just combined, scraping down the sides of the bowl as needed. In a separate bowl, whisk together the 1 ½ cups all-purpose flour, 2 teaspoons baking powder, and ½ teaspoon kosher salt. Gradually add the dry ingredients to the wet ingredients, alternating with the ½ cup buttermilk. Begin and end with the flour mixture. Mix on low speed until just combined, being careful not to overmix, as this can lead to a tough cake.

4. Fold in the Fruit and Assemble

Once the cake batter is ready, gently fold in the macerated rhubarb and raspberries by hand using a spatula. Be careful not to crush the delicate raspberries. Pour the fruit-infused batter into your prepared baking tin, spreading it evenly. Retrieve the chilled streusel topping from the refrigerator and generously sprinkle it over the entire surface of the cake batter.

5. Bake and Cool

Place the prepared buckle in the preheated oven and bake for 45-50 minutes, or until a wooden skewer or toothpick inserted into the center of the cake comes out clean. The streusel topping should be golden brown and the cake should appear set. Keep in mind that due to the moist fruit, a clean toothpick is key to ensure it’s fully cooked through.

Once baked, remove the Raspberry Rhubarb Buckle from the oven and allow it to rest in the tin for 10 minutes. This initial cooling period is important as it allows the cake to set further and continue its internal cooking process, ensuring even moisture distribution. After this short rest, gently lift the buckle out of the tin using the parchment paper handles and transfer it to a wire cooling rack. Allow it to cool completely to room temperature.

Patience is truly a virtue here! It is absolutely vital to let a buckle cool completely before slicing. Because it’s a very moist cake, packed with fresh fruit, cutting it while still warm will result in wet, potentially underbaked portions that can crumble and appear raw. The internal structure needs time to stabilize and the moisture to redistribute evenly throughout the cake. So, resist the temptation, put your patient pants on, and WAIT! The perfect slice is worth the anticipation.

Notes & Tips for a Perfect Raspberry Rhubarb Buckle

Achieving a consistently perfect Raspberry Rhubarb Buckle involves a few helpful tricks and considerations. Here are some detailed notes and tips to ensure your baking success:

• Parchment Paper is Your Best Friend: When lining your baking tin, always ensure the parchment paper extends beyond the top edges of the pan. These makeshift “handles” are crucial for easily lifting the buckle out of the tin after its initial cooling. This prevents the bottom of the cake from becoming soggy as it continues to cool, which is a common issue with moist fruit cakes.
• Don’t Skip Macerating the Fruit: This step might seem minor, but it’s incredibly important. Tossing the chopped rhubarb and raspberries with sugar and letting them sit allows some of their natural liquids to be drawn out. This pre-release of moisture helps prevent the cake batter from becoming too watery during baking, leading to a better texture. Furthermore, it concentrates the fruit’s flavor, making each bite more intense and delicious. I highly recommend macerating any fresh fruit you incorporate into a buckle or similar cake recipe.
• Embrace the Moisture: This cake will naturally have areas that are very moist, especially around the fruit pockets. This is not a sign of an underbaked cake (provided your toothpick test comes out clean) but rather a characteristic of a fruit-filled buckle. The fruit will release additional liquid during baking, which creates these wonderfully tender, juicy pockets. It’s a hallmark of a truly rich and comforting fruit cake.
• Cooling is Non-Negotiable: As mentioned in the method, allowing the buckle to cool completely to room temperature is paramount. Cutting into a warm buckle can lead to a messy, wet, and seemingly underbaked interior because the starches and fats haven’t fully set. Patience ensures a clean slice and a stable, perfectly textured cake.
• Storage: Once completely cooled, store your Raspberry Rhubarb Buckle covered at room temperature for up to 2-3 days. For longer storage, it can be refrigerated for up to a week. To enjoy later, you can also wrap individual slices tightly in plastic wrap and then foil, and freeze for up to 2-3 months. Thaw at room temperature or gently warm in the oven.
• Serving Suggestions: While delicious on its own, a slice of Raspberry Rhubarb Buckle pairs wonderfully with a scoop of vanilla bean ice cream, a dollop of freshly whipped cream, or a light drizzle of crème fraîche.
• Don’t Overmix the Batter: When combining the wet and dry ingredients for the cake batter, mix only until just combined. Overmixing develops the gluten in the flour too much, which can result in a tough, chewy cake rather than a tender, moist one.

Substitutions and Variations for Your Buckle

One of the joys of baking is the ability to adapt recipes to suit your preferences or what you have on hand. This Raspberry Rhubarb Buckle recipe is wonderfully versatile, offering plenty of room for creative substitutions:

• Fruit Variations: If rhubarb isn’t in season, or if you simply want to experiment, feel free to use the base butter cake recipe as a jumping-off point for other fresh fruit buckles. Excellent alternatives include:
  • Strawberries: A classic pairing with rhubarb, or delicious on their own.
  • Blueberries: Offer a delightful burst of sweetness and color.
  • Peaches or Nectarines: When sliced, they create a wonderfully juicy and aromatic buckle.
  • Cherries: Both sweet and tart cherries work beautifully, providing a rich, deep flavor.
  • Mixed Berries: A medley of strawberries, blueberries, blackberries, and raspberries can create a vibrant, complex flavor.

  Remember to macerate any fruit you choose to use to ensure the best results.

• Dairy-Free Buckle: To make this buckle suitable for a dairy-free diet, you can easily swap the dairy components:
  • Butter: Replace with an equal amount of solid vegetable shortening or a good quality plant-based butter alternative (ensure it’s suitable for baking).
  • Buttermilk: Substitute with your preferred nut milk (almond, cashew, or soy milk work well). To achieve the buttermilk-like acidity, add 1 tablespoon of apple cider vinegar or lemon juice to ½ cup of nut milk and let it sit for 5-10 minutes until it slightly curdles. As a note from the original recipe, oat milk is generally not recommended for this specific substitution, likely due to its different fat and protein content affecting the texture.
• Gluten-Free Option: While not explicitly tested in the original recipe, many readers have success using a 1:1 gluten-free all-purpose flour blend (one that contains xanthan gum) as a direct substitution for regular all-purpose flour. Results may vary slightly in texture.
• Spice It Up: Beyond cinnamon in the streusel, consider adding a pinch of nutmeg or cardamom for a different aromatic twist, especially if you’re experimenting with other fruits.
• Nutty Topping: For an extra layer of texture and flavor, add a handful of chopped nuts (pecans, walnuts, or almonds) to your streusel topping.

More Warm Weather Desserts to Enjoy

If you loved this Raspberry Rhubarb Buckle, you’re sure to enjoy these other delightful warm-weather treats:

• Homemade Peach Ice Cream
• Delicious Apricot Cobbler
• Chocolate Peanut Butter Oreo Dirt Pudding
• Classic Ice Cream Soda
• Refreshing Mint Chocolate Chip Ice Cream Cake

Did you try this irresistible Raspberry Rhubarb Buckle recipe? I’d love to hear your thoughts! Please let me know by leaving a review or comment below. And don’t forget to sign up for my newsletter to get more delicious recipes delivered straight to your inbox. You can also follow along on Instagram, Pinterest, and Facebook for daily inspiration!

📖 Recipe

Yield: 1 Cake (approx. 8-10 servings)

Raspberry Rhubarb Buckle

Prep Time:
15 minutes

Cook Time:
50 minutes

Total Time:
1 hour 15 minutes

Raspberry and Rhubarb are a match made in heaven for this perfectly moist and crumbly buckle. While many opt for the popular strawberry pairing, raspberries offer a unique tang that I find simply irresistible!

Ingredients

Crumble Topping:

• ¼ cup Unsalted Butter, soft
• ¼ cup Brown Sugar, packed
• ¼ cup Granulated Sugar
• ½ cup All-Purpose Flour
• ½ teaspoon Cinnamon

Cake:

• 2 cups Fresh Rhubarb, chopped into 1-inch pieces (can use frozen)
• 1 pint Fresh Raspberries (can use frozen)
• ¾ cup Granulated Sugar (for cake batter)
• ¼ cup Granulated Sugar (for fruit maceration)
• ¼ cup Unsalted Butter, softened
• 1 large Egg
• Zest of 1 Lemon
• 1 ½ cups All-Purpose Flour
• 2 teaspoons Baking Powder
• ½ teaspoon Kosher Salt
• ½ cup Buttermilk (or dairy-free alternative)

Instructions

1. Preheat the oven to 350°F (175°C). Lightly grease an 8×8 inch square baking tin with nonstick spray and line it with parchment paper. Be sure to use a long piece of parchment so you can easily lift the cake out of the pan after baking.
2. First, prepare the crumble topping: In a medium bowl, combine the 1/4 cup softened unsalted butter, 1/4 cup packed brown sugar, 1/4 cup granulated sugar, 1/2 cup all-purpose flour, and 1/2 teaspoon cinnamon. Work it together with your hands or a pastry blender until a coarse, paste-like crumble forms. Refrigerate until needed.
3. Before you do anything else, chop your rhubarb and place it in a bowl with 1/4 cup of the granulated sugar and the raspberries. Gently toss to let the fruit macerate just a little bit while you prepare your cake batter.
4. In the bowl of a stand mixer (or with a hand mixer), cream together the remaining 3/4 cup granulated sugar and 1/4 cup softened unsalted butter until light and fluffy.
5. Add the large egg and lemon zest to the creamed mixture and beat until just combined, scraping down the bowl as necessary.
6. In a separate bowl, whisk together the 1 1/2 cups all-purpose flour, 2 teaspoons baking powder, and 1/2 teaspoon kosher salt. Gradually add the dry ingredients to the wet ingredients, alternating with the 1/2 cup buttermilk. Mix on low speed until just combined; do not overmix.
7. Gently fold the chopped rhubarb and raspberries into the cake batter by hand with a spatula.
8. Scoop the batter into the prepared baking pan and top evenly with the chilled crumble mixture.
9. Bake in the preheated oven for 45-50 minutes, or until the streusel is golden brown and a wooden skewer or toothpick inserted into the center of the cake comes out clean.
10. Remove the buckle from the oven and allow it to rest in the baking tin for 10 minutes.
11. After the buckle has rested in the tin, gently lift it out of the pan using the parchment paper handles and allow it to cool completely on a wire cooling rack until it reaches room temperature. This is essential for the buckle’s texture and to prevent a soggy bottom.

Notes

Notes & Tips

When you line the baking tin with parchment, be sure it is lined with some parchment sticking out of the top. This is important because you want to lift the buckle out of the tin after an initial cooling so it doesn’t become soggy. It also prevents the cake from sticking. Leaving the cake in the pan too long can result in a damp bottom layer.

Macerating the fruit is an important step. It allows some of the liquid to be released from the fruit and absorbed by the sugar prior to adding it to the cake batter. This helps concentrate the fruit’s flavor and prevents the cake from becoming overly wet. This technique is beneficial with any fresh fruit you use in a cake.

This cake will have areas that are VERY moist, especially around the fruit. The batter will not be raw if tested properly with a toothpick, but the fruit will release some liquid that will make it seem that way. This moistness is characteristic of a good fruit buckle. This is also why it is crucial to remove the cake from the tin after a few minutes of cooling and let it cool completely on a rack; this allows air circulation and prevents excess moisture from accumulating at the bottom.

Substitutions & Variations

Use the base butter cake recipe here as a fantastic starting point. If rhubarb isn’t in season, or you can’t get your hands on it, you can still make a wonderful buckle! This is essentially a fresh fruit dessert, so feel free to mix in just about any fruit you fancy. Great alternatives include strawberries, blueberries, peaches, or a mix of berries.

If you wanted to make this a dairy-free buckle, you can swap the butter for an equal amount of solid vegetable shortening or a plant-based butter alternative that’s suitable for baking. For the buttermilk, substitute with any nut milk you prefer (like almond or cashew milk) combined with 1 tablespoon of apple cider vinegar or lemon juice to create a dairy-free “buttermilk.” The original recipe advises against using oat milk for this substitution, likely due to textural differences.

Recommended Products

As an Amazon Associate and member of other affiliate programs, I earn from qualifying purchases.

• Ateco 8 by 8 by 3-Inch Professional Square Pan Baking Supply, 8 x 8 inch, Silver
• Kootek 200 Pcs Parchment Paper Sheets, 12 X 16 Inch Non-Stick Baking Sheet, Pre-cut Parchment Liner Unbleached Baker Papers for Grilling Air Fryer Steaming Cooking Bread Cake and Cookies
• Ateco Stainless Steel Cake Tester – 7 Inch, Set of 3

Did you make this recipe?

Please leave a comment on the blog or share a photo on Instagram