Classic German Rhubarb Cake

I didn’t taste rhubarb until I was in my twenties. Growing up, my mom wasn’t really into baking with things from the garden, so rhubarb was just one of those mysterious ingredients I’d hear about but never actually eat.

Then I moved to Portland, and suddenly everyone had rhubarb growing in their backyard. My neighbor brought over a huge bundle one spring, and I had no idea what to do with it. That’s when I discovered this German rhubarb cake recipe, and it completely changed my mind about this tart, pink vegetable that everyone treats like a fruit.

The best part? It’s got a buttery cake base, tangy rhubarb in the middle, and a cinnamon streusel on top. It’s the kind of cake that tastes like you spent hours in the kitchen, but it actually comes together pretty quickly.

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What Kind of Rhubarb Should I Use?

Fresh rhubarb is always your best bet for this German cake, and you’ll find it in season during spring and early summer at most grocery stores and farmers markets. The color of the stalks doesn’t really matter – some rhubarb is bright red while other varieties are more green or pink, and they all taste pretty similar. Just make sure your rhubarb stalks are firm and crisp, not limp or dried out at the ends. If you only have access to frozen rhubarb, that’ll work too – just thaw it completely and drain off any excess liquid before adding it to your batter so your cake doesn’t get soggy.

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Options for Substitutions

This cake is pretty forgiving when it comes to swapping ingredients:

• Buttermilk: Don’t have buttermilk? Make your own by adding 1 tablespoon of lemon juice or white vinegar to regular milk and letting it sit for 5 minutes. You can also use plain yogurt thinned with a bit of milk.
• Rhubarb: Fresh rhubarb is best here, but frozen works too – just thaw it completely and drain off any excess liquid before using. You could also mix in some strawberries with the rhubarb for a sweeter flavor.
• Butter: You can use margarine or coconut oil in place of butter, though butter gives the best flavor. If using coconut oil, make sure it’s in solid form when making the crumb topping.
• Vanilla essence: Vanilla extract works just the same. If you’re out of both, try almond extract but use only 1/2 teaspoon as it’s stronger.
• Baking powder and baking soda: These two work together in this recipe, so it’s best not to substitute them. They’re what gives the cake its rise and texture.

Watch Out for These Mistakes While Baking

The biggest mistake when baking with rhubarb is not cutting it into uniform pieces – aim for 1/2-inch chunks so they cook evenly and don’t release too much moisture in some spots while staying tough in others.

Overmixing the batter after adding the flour will develop too much gluten and make your cake dense and chewy instead of tender, so stir just until the ingredients are combined and you don’t see any dry flour.

Since rhubarb releases liquid as it bakes, check for doneness by inserting a toothpick into the cake part (not through a piece of rhubarb) – it should come out with just a few moist crumbs, not wet batter.

For the best crumb topping, make sure your butter is cold and use your fingers or a fork to create pea-sized clumps rather than a sandy mixture, which gives you those nice crunchy bits everyone loves.

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What to Serve With German Rhubarb Cake?

This cake is perfect for an afternoon coffee break or as a simple dessert after dinner. A dollop of freshly whipped cream or a scoop of vanilla ice cream on top really complements the tart rhubarb flavor and makes it feel a bit more special. I like serving it alongside a hot cup of coffee or tea, which balances out the sweetness of the cake. If you’re having people over for brunch, this cake pairs nicely with scrambled eggs and bacon for a sweet and savory spread.

Storage Instructions

Store: Keep your rhubarb cake covered with plastic wrap or in an airtight container at room temperature for up to 2 days. If you want it to last longer, pop it in the fridge where it’ll stay fresh for about 5 days.

Freeze: This cake freezes really well! Wrap individual slices in plastic wrap and then place them in a freezer bag, or freeze the whole cake wrapped tightly. It’ll keep for up to 3 months in the freezer.

Serve: Let frozen slices thaw at room temperature for about an hour, or overnight in the fridge if you’re planning ahead. I actually think this cake tastes great cold straight from the fridge, but you can also warm it up in the microwave for about 15-20 seconds if you prefer it warm.

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 2750-2950
• Protein: 28-32 g
• Fat: 110-120 g
• Carbohydrates: 410-440 g

Ingredients

For the cake:

• 1/2 cup butter (I like Kerrygold unsalted butter for this)
• 1 1/4 cups sugar
• 1 tsp vanilla
• 1 egg (room temperature, about 70°F)
• 2 cups flour (I always use King Arthur all-purpose flour)
• 1 tsp baking powder
• 1/2 tsp baking soda
• 1/2 tsp salt
• 1 cup buttermilk
• 1/2 teaspoon lemon zest
• 2.5 cups rhubarb (trimmed and cut into 1/2-inch pieces)

For the streusel topping:

• 1/4 cup butter (cold, cut into 1/4-inch cubes)
• 1/2 cup flour
• 3/4 cup sugar
• 1/2 teaspoon ground cinnamon

Step 1: Prepare Pan and Mise en Place

• 1 baking pan
• 2.5 cups rhubarb
• 2 cups flour
• 1 tsp baking powder
• 1/2 tsp baking soda
• 1/2 tsp salt

Preheat oven to 350°F and grease a 9×13 inch baking dish or similar size cake pan with butter or cooking spray.

While the oven heats, trim the rhubarb and cut it into 1/2-inch pieces, then measure out all dry ingredients (flour, baking powder, baking soda, salt) into a small bowl.

This prep work ensures everything is ready when you need it, preventing delays during mixing.

Step 2: Cream Butter and Sugar

• 1/2 cup butter
• 1 1/4 cups sugar

In a large mixing bowl, combine the butter and sugar, beating on medium speed for 2-3 minutes until the mixture is light, fluffy, and pale in color.

This creaming process incorporates air into the batter, which helps the cake rise and creates a tender crumb.

I like to use Kerrygold unsalted butter because its rich flavor really shines through in this simple cake.

Step 3: Incorporate Egg and Vanilla

• 1 egg
• 1 tsp vanilla
• 1/2 teaspoon lemon zest

Add the room temperature egg and vanilla to the creamed mixture and beat until fully combined, about 1-2 minutes.

A room temperature egg emulsifies more easily with the butter mixture, creating a smoother batter.

Make sure to scrape down the sides of the bowl to ensure all ingredients are evenly incorporated.

Step 4: Combine Dry and Wet Mixtures

• dry ingredient mixture from Step 1
• 1 cup buttermilk

Alternately add the dry ingredient mixture from Step 1 and the buttermilk to the wet mixture, beginning and ending with the dry ingredients.

Add in three additions of dry mixture with two additions of buttermilk, stirring gently until just combined after each addition.

I always use King Arthur all-purpose flour because it has consistent protein content, which helps give this cake its tender but sturdy structure.

Be careful not to overmix, as this can develop gluten and make the cake tough.

Step 5: Add Rhubarb and Prepare Topping

• rhubarb from Step 1
• 1/4 cup butter
• 1/2 cup flour
• 3/4 cup sugar
• 1/2 teaspoon ground cinnamon

Gently fold the prepared rhubarb pieces into the batter using a spatula or wooden spoon, being careful not to break up the pieces too much.

In a separate small bowl, combine the cold butter cubes, flour, sugar, and cinnamon for the topping, mixing with a fork until the mixture resembles coarse breadcrumbs.

Pour the batter into the prepared pan and spread it evenly.

Step 6: Add Topping and Bake

• topping mixture from Step 5

Sprinkle the cinnamon-butter topping mixture evenly over the batter, breaking up any larger clumps as you go.

Bake in the preheated 350°F oven for 35-45 minutes, until the cake is golden brown and a toothpick inserted in the center comes out clean or with just a few moist crumbs.

The cake is done when the topping is golden and the cake pulls slightly away from the sides of the pan.

Step 7: Cool and Serve

Remove the cake from the oven and let it cool in the pan for at least 15-20 minutes before serving.

This allows the cake to set and makes it easier to cut clean slices.

Serve warm or at room temperature, optionally with whipped cream, vanilla ice cream, or a dusting of powdered sugar.

Classic German Rhubarb Cake

Delicious Classic German Rhubarb Cake recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 20 minutes mins

Cook Time 35 minutes mins

Total Time 57 minutes mins

Servings 10 slices

Calories 2850 kcal

Ingredients

  

For the cake::

• 1/2 cup butter (I like Kerrygold unsalted butter for this)
• 1 1/4 cups sugar
• 1 tsp vanilla
• 1 egg (room temperature, about 70°F)
• 2 cups flour (I always use King Arthur all-purpose flour)
• 1 tsp baking powder
• 1/2 tsp baking soda
• 1/2 tsp salt
• 1 cup buttermilk
• 1/2 teaspoon lemon zest
• 2.5 cups rhubarb (trimmed and cut into 1/2-inch pieces)

For the streusel topping::

• 1/4 cup butter (cold, cut into 1/4-inch cubes)
• 1/2 cup flour
• 3/4 cup sugar
• 1/2 teaspoon ground cinnamon

Instructions

 

• Preheat oven to 350°F and grease a 9x13 inch baking dish or similar size cake pan with butter or cooking spray. While the oven heats, trim the rhubarb and cut it into 1/2-inch pieces, then measure out all dry ingredients (flour, baking powder, baking soda, salt) into a small bowl. This prep work ensures everything is ready when you need it, preventing delays during mixing.
• In a large mixing bowl, combine the butter and sugar, beating on medium speed for 2-3 minutes until the mixture is light, fluffy, and pale in color. This creaming process incorporates air into the batter, which helps the cake rise and creates a tender crumb. I like to use Kerrygold unsalted butter because its rich flavor really shines through in this simple cake.
• Add the room temperature egg and vanilla to the creamed mixture and beat until fully combined, about 1-2 minutes. A room temperature egg emulsifies more easily with the butter mixture, creating a smoother batter. Make sure to scrape down the sides of the bowl to ensure all ingredients are evenly incorporated.
• Alternately add the dry ingredient mixture from Step 1 and the buttermilk to the wet mixture, beginning and ending with the dry ingredients. Add in three additions of dry mixture with two additions of buttermilk, stirring gently until just combined after each addition. I always use King Arthur all-purpose flour because it has consistent protein content, which helps give this cake its tender but sturdy structure. Be careful not to overmix, as this can develop gluten and make the cake tough.
• Gently fold the prepared rhubarb pieces into the batter using a spatula or wooden spoon, being careful not to break up the pieces too much. In a separate small bowl, combine the cold butter cubes, flour, sugar, and cinnamon for the topping, mixing with a fork until the mixture resembles coarse breadcrumbs. Pour the batter into the prepared pan and spread it evenly.
• Sprinkle the cinnamon-butter topping mixture evenly over the batter, breaking up any larger clumps as you go. Bake in the preheated 350°F oven for 35-45 minutes, until the cake is golden brown and a toothpick inserted in the center comes out clean or with just a few moist crumbs. The cake is done when the topping is golden and the cake pulls slightly away from the sides of the pan.
• Remove the cake from the oven and let it cool in the pan for at least 15-20 minutes before serving. This allows the cake to set and makes it easier to cut clean slices. Serve warm or at room temperature, optionally with whipped cream, vanilla ice cream, or a dusting of powdered sugar.