Oma's Rhubarb Cake + Simple Recipe + 10 Minutes Prep

Name: Oma's Rhubarb Cake
Prep time: 10 min
Cook time: PT-486117H40M54S
Total time: 45 min
Cuisine: German-American
Ingredients: 3 cups rhubarb, chopped; 1 tbsp sugar (for rhubarb); 2 cups all-purpose flour; 1 tsp baking soda; 1/2 tsp salt; 1 egg; 1 cup buttermilk; 1 tsp vanilla extract; 1/2 cup butter, softened; 1 cup granulated sugar

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There’s something magical about baking from a handwritten recipe card, especially one labeled “Oma’s Rhubarb Cake.” The first time I made it, I didn’t expect much—just a simple dessert to use up fresh rhubarb. But one bite in, and I knew it was something special. I’ve since learned the secret: letting the sliced rhubarb sit in a little sugar before baking helps mellow the tartness and coax out a deep, almost jammy flavor.

If you’ve got a handful of rhubarb and a craving for a rustic dessert that sings of spring, this cake is a must-try.

Why You’ll Love Oma’s Rhubarb Cake

Oma’s Rhubarb Cake is more than just a dessert—it’s a nostalgic bite of old-world baking tradition. With its roots in German kitchens, this cake balances tart, garden-fresh rhubarb with a fluffy, buttery crumb and just the right hint of sweetness.

It’s a perfect recipe for:

Celebrating rhubarb season, which runs from April through June

Sharing at family brunches, Sunday coffee tables, or church picnics
Pairing with coffee or tea thanks to its lightly sweet, moist crumb

Plus, it’s incredibly simple. No complicated techniques, no fancy ingredients—just honest, wholesome flavor that delivers every time.

Looking for inspiration? Try Homemade Strawberry Rhubarb Jam for a tangy topping twist.

Ingredients and Substitutions

Here’s what you’ll need to bake this delicious cake:

Fresh rhubarb, chopped

Granulated sugar
All-purpose flour
Baking soda

Salt
Egg
Buttermilk or milk + lemon juice

Vanilla extract
Butter or margarine

Don’t have one of these ingredients? No problem! Here’s a handy guide to help you adapt based on what’s in your pantry:

Ingredient Substitution Table

Ingredient	Substitution	Notes
Fresh rhubarb	Frozen rhubarb (thawed & drained)	Drain excess moisture before using
Buttermilk	1 cup milk + 1 tbsp lemon juice	Let sit 5 minutes before using
Granulated sugar	Coconut sugar or light brown sugar	Flavor will be slightly deeper
All-purpose flour	1:1 gluten-free baking blend	For gluten-free version
Butter	Margarine or plant-based butter	Keep cold for best texture
Egg	1 flax egg (1 tbsp flax + 3 tbsp water)	For vegan adaptation

Check out Best Rhubarb Bread if you’re interested in more delicious rhubarb bakes.

Step-by-Step Baking Instructions

Here’s how to bring Oma’s Rhubarb Cake to life in your own kitchen.

Prep the rhubarb
Chop about 3 cups of rhubarb into small chunks. Toss them with a tablespoon of sugar and set aside. This draws out extra moisture and tames the tartness.

Preheat the oven
Set your oven to 350°F (175°C). Grease and flour a 9×13-inch baking dish or line it with parchment.
Mix the wet ingredients
In a medium bowl, beat 1 egg with sugar, buttermilk, and vanilla extract. Whisk until smooth.
Combine dry ingredients
In a separate bowl, sift together flour, baking soda, and salt. Stir into the wet mixture until just combined.

Fold in rhubarb
Gently stir in the sugared rhubarb chunks, ensuring even distribution.
Pour and sprinkle
Pour batter into the prepared pan. Optionally, sprinkle with extra sugar and cinnamon for a subtle crunch on top.
Bake and cool
Bake for 35–40 minutes or until a toothpick comes out clean. Let cool in pan before slicing.

Discover great ideas like Rhubarb Oat Bars if you’re baking in bulk.

External Tip

The USDA offers a seasonal produce guide that’s helpful for selecting peak rhubarb and storing it properly.

Storage, Freezing, and Make-Ahead Tips

One of the best things about Oma’s Rhubarb Cake is how well it stores, making it perfect for preparing in advance or sharing over several days. Here’s how to keep it at its best:

On the Counter
Once cooled, store your cake in an airtight container at room temperature for up to 2 days. The cake will remain moist, and the flavors will continue to meld.
In the Refrigerator
For longer storage, keep the cake in the fridge for up to a week. It will keep its texture but may lose a bit of its fresh-from-the-oven charm.
Freezing for Later
You can freeze this cake for up to 3 months! Wrap individual slices tightly in plastic wrap, then foil, and store in a freezer-safe container. To thaw, simply leave it at room temperature or microwave for 15 seconds.

Make-Ahead Tips
Make the cake a day ahead to deepen the flavors. The rhubarb settles into the batter, and the cake develops a nice, tender crumb that’s even more delicious the next day.

Common Mistakes and How to Fix Them

Even simple recipes can pose challenges. Here are some common mistakes when baking Oma’s Rhubarb Cake and how to avoid them:

1. Soggy Cake Base

Solution: Don’t skip the step of sprinkling sugar over the rhubarb before baking. This helps draw out excess moisture and prevents a soggy base.

2. Overly Tart Flavor

Solution: Make sure to adjust the sugar in your recipe if your rhubarb is particularly sour. You can also balance tartness by adding a sweet topping like a drizzle of vanilla glaze or whipped cream.

3. Rhubarb Sinking

Solution: Toss the rhubarb in a little flour before folding it into the batter. This will help it stay evenly distributed and not sink to the bottom of the pan.

4. Burnt Edges or Overbaking

Solution: Every oven is different. If the edges begin to brown too quickly, cover the cake with aluminum foil in the final 10 minutes of baking. Always check doneness with a toothpick.

Serving Suggestions and Variations

Oma’s Rhubarb Cake is fantastic on its own, but there are plenty of ways to elevate it:

1. With Whipped Cream

Top each slice with a dollop of freshly whipped cream or even a scoop of vanilla ice cream for extra indulgence.

2. Adding Other Fruits

Feel free to experiment with fruit additions. Try adding strawberries for a classic rhubarb-strawberry combination or orange zest for a fresh twist.

3. As Muffins or Bars

This cake recipe can easily be adapted for individual servings. Pour the batter into muffin tins or a smaller pan and bake until golden brown. Muffins or bars are great for on-the-go!

Nutrition Facts

Here’s an estimate of the nutritional breakdown for Oma’s Rhubarb Cake (per serving):

Nutrient	Amount
Calories	240 kcal
Total Fat	9g
Saturated Fat	5g
Cholesterol	55mg
Sodium	150mg
Carbohydrates	35g
Fiber	2g
Sugars	20g
Protein	3g

Note: Nutrition values are estimates and may vary based on ingredient substitutions or portion sizes.

FAQ: Your Oma’s Rhubarb Cake Questions Answered

What kind of rhubarb works best for this cake?

Any type of fresh rhubarb will work. Red stalks tend to be sweeter, but green rhubarb is perfectly fine, though slightly more tart.

Can I use frozen rhubarb instead of fresh?

Yes, you can. Be sure to thaw and drain frozen rhubarb to prevent excess moisture in the cake.

Why is my cake sinking in the middle?

This can happen if the cake batter is overmixed, or if you use too much rhubarb. Be gentle when mixing and make sure your rhubarb is well-drained.

Conclusion

Oma’s Rhubarb Cake is the perfect combination of sweet, tangy, and nostalgic—ideal for spring gatherings or cozy afternoons. Whether you’re sharing it with family or enjoying it as a treat to yourself, this cake is sure to become a staple in your kitchen.

Don’t miss our Rhubarb Muffins for more rhubarb-based treats that everyone will love!