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I adore this Oma’s rhubarb cake because it tastes like a confident, old-school dessert nobody tries to explain. I love the sharp, almost tart rhubarb folding into a batter that somehow stays ridiculously moist.

And the topping of brown sugar caramelizes in patches, creating sweet, crackly bites that make the slice worth stealing. My husband’s grandmother called me for the recipe and I still flex about that.

It isn’t precious. It’s honest, unapologetic cake that pulls you back for another forkful.

I eat it with a stupid grin. Try not to drool?

Impossible. Worth every sinful, ridiculous, glorious bite, truly.

Ingredients

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Rhubarb: tart bite that wakes the cake up, juicy and pleasantly tangy.
Flour: basic structure, keeps it from collapsing while staying tender.
Sugar: sweetens and browns the top, makes it feel like dessert.
Baking powder: gives lift so the cake isn’t dense or heavy.
Baking soda: little boost for browning and slight tenderness.
Salt: balances sweetness and brings out the rhubarb’s flavor.
Eggs: bind everything together, add protein and a soft crumb.
Butter (melted): adds richness and a homey, buttery mouthfeel.
Sour cream: moistness and tang, keeps crumbs soft the next day.
Vanilla: warm aroma that makes it smell like Grandma’s kitchen.
Brown sugar (topping): caramel notes and sticky sweet crunch up top.
Flour (topping): basic crumb base that holds the crunchy bits together.
Cold butter (topping): makes the topping crumbly, little buttery pockets.
Cinnamon: cozy warmth, pairs nicely with the rhubarb’s tartness.
Optional nuts/oats: add crunch and chew, plus a rustic finish.

Ingredient Quantities

2 cups rhubarb, chopped

2 cups all purpose flour

1 1/4 cups granulated sugar

2 teaspoons baking powder

1/2 teaspoon baking soda

1/2 teaspoon salt

2 large eggs

1/2 cup unsalted butter, melted and cooled

1 cup sour cream

1 teaspoon vanilla extract

For the topping: 1/2 cup packed brown sugar

For the topping: 1/2 cup all purpose flour

For the topping: 1/4 cup cold unsalted butter, cut into small pieces

For the topping: 1 teaspoon ground cinnamon

Optional: 1/2 cup chopped walnuts or oats for added crunch

How to Make this

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1. Preheat oven to 350°F (175°C). Grease and flour a 9×13 inch baking pan or line it with parchment.

2. Toss 2 cups chopped rhubarb with 1 to 2 tablespoons of the granulated sugar to draw out moisture and set aside.

3. In a medium bowl whisk together 2 cups all purpose flour, 1 1/4 cups granulated sugar, 2 teaspoons baking powder, 1/2 teaspoon baking soda, and 1/2 teaspoon salt.

4. In a separate bowl beat 2 large eggs, then stir in 1/2 cup melted and cooled unsalted butter, 1 cup sour cream, and 1 teaspoon vanilla extract until smooth.

5. Fold the wet ingredients into the dry ingredients until just combined. Gently fold in the drained chopped rhubarb.

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

7. For the topping, combine 1/2 cup packed brown sugar, 1/2 cup all purpose flour, and 1 teaspoon ground cinnamon. Cut in 1/4 cup cold unsalted butter with a pastry cutter or fork until the mixture resembles coarse crumbs. Stir in optional 1/2 cup chopped walnuts or oats if using.

8. Sprinkle the topping evenly over the batter.

9. Bake for 35 to 45 minutes or until a toothpick inserted near the center comes out clean and the topping is golden. Cool in the pan on a wire rack for at least 20 minutes before slicing and serving.

Equipment Needed

1. 9×13 inch baking pan (or parchment-lined equivalent)
2. Mixing bowls (one large, one medium)
3. Measuring cups and spoons
4. Whisk
5. Rubber spatula or flexible spatula
6. Wooden spoon or silicone spoon for folding
7. Chef knife and cutting board for chopping rhubarb
8. Pastry cutter or fork for the crumb topping
9. Wire cooling rack
10. Toothpick or cake tester

FAQ

Q: What pan size and oven temperature should I use? A: Bake in a 9×13 inch pan at 350°F (175°C) for 35 to 45 minutes, or until a toothpick in the center comes out clean.

Q: How should I prepare the rhubarb so the cake does not become soggy? A: Chop rhubarb into roughly 1/2 inch pieces and pat dry if very wet. Toss with 1 to 2 teaspoons flour from the recipe before folding into the batter to help absorb excess moisture.

Q: Can I substitute the sour cream and butter? A: For sour cream use plain Greek yogurt in equal measure. Melted butter can be replaced with an equal amount of neutral oil, but flavor will be slightly different. If using oil, reduce baking time by a few minutes if the top browns less.

Q: Can I add nuts or oats to the topping? A: Yes. Fold up to 1/2 cup chopped walnuts or 1/2 cup old fashioned oats into the brown sugar topping for extra crunch. Either works alone or together.

Q: How do I store and reheat the cake? A: Store covered at room temperature for up to 2 days, or refrigerate up to 5 days. Reheat individual slices in a 325°F (160°C) oven for 8 to 10 minutes or microwave 20 to 30 seconds until warm.

Q: Can I freeze the cake and how? A: Freeze whole or sliced after fully cooling. Wrap tightly in plastic and foil or use an airtight container. Freeze up to 3 months. Thaw overnight in the refrigerator and bring to room temperature before serving, or warm briefly in the oven.

Oma’s Rhubarb Cake Recipe Substitutions and Variations

Rhubarb: substitute 2 cups chopped tart apples or 2 cups chopped rhubarb mixed with 1 cup strawberries for a sweeter, less acidic filling.
Sour cream: substitute 1 cup plain Greek yogurt or 1 cup buttermilk thinned to similar consistency for similar tang and moisture.
Unsalted butter (melted): substitute 1/2 cup neutral-flavored oil such as canola or light olive oil for equal fat and moisture, or use 1/2 cup melted salted butter and reduce added salt slightly.
Optional walnuts or oats: substitute 1/2 cup chopped pecans or 1/2 cup toasted sliced almonds, or use 1/2 cup shredded coconut for different texture and flavor.

Pro Tips

1. Pat the rhubarb dry after macerating it so the batter does not become too wet; a light squeeze in a clean kitchen towel or paper towel removes excess moisture without sacrificing the tart bite.

2. Use room temperature eggs, butter, and sour cream so the batter emulsifies smoothly; it helps prevent overmixing and keeps the crumb tender.

3. If you like more contrast in texture, toast the walnuts or oats lightly before adding them to the streusel; they will taste nuttier and stay crunchier after baking.

4. Rotate the pan halfway through baking and start checking for doneness 5 to 10 minutes before the minimum time; ovens vary and this prevents overbaking while keeping the topping golden.

Oma's Rhubarb Cake Recipe

Recipe by Tina Bueller

0.0 from 0 votes

Servings

servings

Calories

329

kcal

Equipment: 1. 9×13 inch baking pan (or parchment-lined equivalent)
2. Mixing bowls (one large, one medium)
3. Measuring cups and spoons
4. Whisk
5. Rubber spatula or flexible spatula
6. Wooden spoon or silicone spoon for folding
7. Chef knife and cutting board for chopping rhubarb
8. Pastry cutter or fork for the crumb topping
9. Wire cooling rack
10. Toothpick or cake tester

Ingredients

2 cups rhubarb, chopped
2 cups all purpose flour
1 1/4 cups granulated sugar
2 teaspoons baking powder
1/2 teaspoon baking soda
1/2 teaspoon salt
2 large eggs
1/2 cup unsalted butter, melted and cooled
1 cup sour cream
1 teaspoon vanilla extract
For the topping: 1/2 cup packed brown sugar
For the topping: 1/2 cup all purpose flour
For the topping: 1/4 cup cold unsalted butter, cut into small pieces
For the topping: 1 teaspoon ground cinnamon
Optional: 1/2 cup chopped walnuts or oats for added crunch

Directions

Preheat oven to 350°F (175°C). Grease and flour a 9×13 inch baking pan or line it with parchment.
Toss 2 cups chopped rhubarb with 1 to 2 tablespoons of the granulated sugar to draw out moisture and set aside.
In a medium bowl whisk together 2 cups all purpose flour, 1 1/4 cups granulated sugar, 2 teaspoons baking powder, 1/2 teaspoon baking soda, and 1/2 teaspoon salt.
In a separate bowl beat 2 large eggs, then stir in 1/2 cup melted and cooled unsalted butter, 1 cup sour cream, and 1 teaspoon vanilla extract until smooth.
Fold the wet ingredients into the dry ingredients until just combined. Gently fold in the drained chopped rhubarb.
Pour the batter into the prepared pan and spread evenly.
For the topping, combine 1/2 cup packed brown sugar, 1/2 cup all purpose flour, and 1 teaspoon ground cinnamon. Cut in 1/4 cup cold unsalted butter with a pastry cutter or fork until the mixture resembles coarse crumbs. Stir in optional 1/2 cup chopped walnuts or oats if using.
Sprinkle the topping evenly over the batter.
Bake for 35 to 45 minutes or until a toothpick inserted near the center comes out clean and the topping is golden. Cool in the pan on a wire rack for at least 20 minutes before slicing and serving.

Notes

Below you’ll find my best estimate of this recipe’s nutrition facts. Treat the numbers as a guide rather than a rule—great food should nourish both body and spirit. Figures are approximate, and the website owner assumes no liability for any inaccuracies in this recipe.