Rhubarb Crumb Cake

Rhubarb Crumb Cake is a delightful treat that perfectly balances tart and sweet flavors with a buttery crumb topping. This cake is tender, moist, and bursting with the fresh zing of rhubarb, making it an irresistible dessert or breakfast option. Whether you’re a seasoned baker or just looking for a fresh seasonal recipe, this Rhubarb Crumb Cake will impress everyone at your table with its inviting aroma and luscious crumbly texture.

Reasons to Love Rhubarb Crumb Cake

Rhubarb Crumb Cake is a true crowd-pleaser for many reasons. First, it combines the tangy brightness of rhubarb with a sweet, buttery crumb topping that creates a perfect flavor contrast. The cake itself is tender and moist, thanks to buttermilk and cake flour, which produce a delicate crumb. It’s also incredibly versatile — serve it warm with a dusting of powdered sugar for breakfast, or pair it with a scoop of vanilla ice cream for dessert. Plus, this cake uses simple pantry ingredients and fresh rhubarb, making it a seasonal favorite that’s easy to whip up. If you adore seasonal fruit desserts, you might also enjoy the Brown Butter Pear Crumble — another comforting recipe with a luscious crumb topping.

What You’ll Need

• For the Crumb Topping:
  • 2/3 cup (66.67g) granulated sugar
  • 1/3 cup (73.33g) dark brown sugar
  • 1/2 teaspoon ground cinnamon
  • 1/4 teaspoon ground ginger
  • Pinch of salt
  • 8 tablespoons unsalted butter, melted and still warm
  • 1 cup (218.75g) cake flour
  • 1 cup (183g) small-diced rhubarb
  • 2 tablespoons granulated sugar (for rhubarb layer)
  • 1 teaspoon cornstarch
  • 1/4 teaspoon ground ginger (for rhubarb layer)
  • 2 teaspoons all-purpose flour (for rhubarb layer)
• For the Cake:
  • 1 cup (156.25g) cake flour
  • 1/2 cup (100g) granulated sugar
  • 1/4 teaspoon baking soda
  • 1/4 teaspoon table salt
  • 6 tablespoons unsalted butter, cut into 6 pieces, softened but still cool
  • 1 egg
  • 1 egg yolk
  • 1 teaspoon vanilla extract
  • 1/3 cup (80ml) buttermilk
• Powdered sugar, for dusting

Before You Start: Equipment

• 9-inch square baking pan – Perfect size for even baking and portioning.
• Mixing bowls – One large for the cake batter and one for the crumb topping.
• Whisk and spatula – To combine ingredients smoothly.
• Measuring cups and spoons – For precise ingredient measurements.
• Electric mixer or hand whisk – To cream butter and sugar easily.
• Sharp knife – For dicing rhubarb into small pieces.

Step-by-Step: Rhubarb Crumb Cake

Step 1: Prepare the crumb topping

In a medium bowl, whisk together 2/3 cup granulated sugar, 1/3 cup dark brown sugar, 1/2 teaspoon cinnamon, 1/4 teaspoon ground ginger, and a pinch of salt. Stir in 1 cup cake flour until combined. Slowly pour in the 8 tablespoons melted butter and mix until the mixture resembles coarse crumbs. Set aside.

Step 2: Prepare the rhubarb layer

In a separate bowl, toss the diced rhubarb with 2 tablespoons sugar, 1 teaspoon cornstarch, 1/4 teaspoon ground ginger, and 2 teaspoons all-purpose flour. This will help thicken the rhubarb juices as it bakes. Set aside.

Step 3: Make the cake batter

In a large mixing bowl, sift together 1 cup cake flour, 1/2 cup granulated sugar, 1/4 teaspoon baking soda, and 1/4 teaspoon salt. Add the softened butter pieces and use a hand mixer or stand mixer to beat the mixture until it’s crumbly.

Step 4: Add wet ingredients

In a small bowl, whisk together the egg, egg yolk, vanilla extract, and buttermilk. Gradually add this mixture to the flour and butter crumbs, mixing on medium speed until the batter is smooth and well combined.

Step 5: Assemble the cake

Spread half of the cake batter evenly into the prepared baking pan. Carefully spoon the rhubarb mixture over the batter, distributing it evenly. Dollop the remaining batter on top of the rhubarb layer and gently spread it out without mixing the layers.

Step 6: Add the crumb topping

Sprinkle the crumb topping evenly over the top layer of batter. The crumb topping will bake into a golden, buttery crust.

Step 7: Bake

Preheat your oven to 350°F (175°C). Bake the cake for 45 to 50 minutes, or until a toothpick inserted into the center comes out clean or with just a few moist crumbs. The top should be golden brown and crisp.

Step 8: Cool and serve

Allow the cake to cool in the pan for at least 20 minutes before dusting with powdered sugar. Serve warm or at room temperature. This cake pairs beautifully with a cup of tea or coffee, or even a scoop of vanilla ice cream on the side. If you love fruit desserts with a crumbly finish, don’t miss trying the Brown Butter Honey Nectarine Cobbler for another sweet delight.

Texture-Safe Substitutions

• All-purpose flour: Can be used instead of cake flour but expect a slightly denser crumb.
• Butter: Use a plant-based butter alternative if dairy-free is preferred, keeping the same measurements.
• Buttermilk: Substitute with 3/4 cup milk plus 1 tablespoon lemon juice or vinegar for a homemade version.
• Eggs: Use an egg replacer equivalent to 1 egg if necessary, but eggs add richness and structure.
• Rhubarb: Substitute with tart fruits like green apple or sour cherries if rhubarb is unavailable.

Don’t Do This

• Don’t overmix the cake batter once the wet and dry ingredients are combined — overmixing will create a tough cake.
• Do not skip cornstarch in the rhubarb layer; it prevents the cake from becoming soggy.
• Avoid using canned or frozen rhubarb without draining excess moisture, as this will water down your cake.
• Do not increase the oven temperature in an attempt to speed up baking; the crumb topping may burn before the cake is cooked through.

Storage Pro Tips

Store leftover Rhubarb Crumb Cake covered tightly at room temperature for up to 2 days. For longer storage, place the cake in an airtight container and refrigerate for up to 5 days. To revive the crumb topping’s crispness after refrigeration, warm slices briefly in a toaster oven or conventional oven. The cake also freezes beautifully—wrap it tightly in plastic wrap and foil, then freeze for up to 3 months. Thaw overnight in the refrigerator before serving.

Your Questions, Answered

Can I make Rhubarb Crumb Cake ahead of time?

Absolutely! You can prepare the cake the day before and let it cool completely. Store it covered at room temperature or refrigerated depending on how soon you plan to serve it. Reheating a slice in the oven or microwave will refresh the crumb topping nicely.

How do I dice rhubarb properly for this cake?

Wash the rhubarb stalks thoroughly, then trim off the leaves (they’re not edible). Cut the stalks into small, uniform pieces about 1/4 inch in size to ensure even baking and distribution throughout the cake.

What can I use instead of buttermilk?

If you don’t have buttermilk on hand, mix 3/4 cup milk with 1 tablespoon lemon juice or white vinegar. Let it sit for 5 minutes until it thickens and curdles slightly—this mimics the acidity of buttermilk, which helps tenderize the cake.

Is it okay to skip the crumb topping?

The crumb topping adds a wonderful texture and sweetness contrast to the cake. While you technically can bake the cake without it, you’ll miss out on the signature buttery, crunchy finish that makes Rhubarb Crumb Cake so special.

Because You Liked This

• Brown Butter Honey Nectarine Cobbler – A luscious cobbler with warm brown butter and juicy nectarines.
• Brown Butter Pear Crumble – A cozy pear dessert with a nutty brown butter topping.

Let’s Eat

There’s nothing quite like slicing into this Rhubarb Crumb Cake and savoring the perfect combination of tart rhubarb, tender cake, and buttery crumb topping. Dusted with powdered sugar, each bite is a blissful balance of textures and flavors that will keep you coming back for more. Whether you’re sharing with family or enjoying a quiet moment with a cup of tea, this cake celebrates the best of rhubarb’s season in every crumb. So grab your fork, dig in, and enjoy the magic of homemade Rhubarb Crumb Cake!

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