This rhubarb cake with butter sauce is a tender yellow layer cake studded with tart rhubarb and finished with a warm, glossy butter sauce.
The layers bake in two 9 inch pans in about 30 minutes, and the sauce simmers on the stove in just a few minutes. Plan on about 2 hours in total, including the time the layers need to cool.
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Why This Rhubarb Cake with Butter Sauce Recipe Works
Tart rhubarb meets a sweet cake. Chopped rhubarb softens as it bakes and adds pockets of tang that balance the rich crumb.
The butter sauce adds richness. Butter, sugar, and cream simmer into a smooth, pourable sauce that soaks into the top of each slice.
It uses simple pantry ingredients. Flour, sugar, butter, eggs, and milk are all you need, plus rhubarb in season.
Ingredients for Rhubarb Cake with Butter Sauce
- 3 cups all purpose flour
- 1 1/2 cups granulated sugar
- 1 cup unsalted butter, softened
- 4 large eggs, at room temperature
- 1 cup whole milk
- 3 teaspoons baking powder
- 1/2 teaspoon kosher salt
- 1 teaspoon vanilla extract, for the cake
- 2 cups chopped rhubarb, stalks only, in 1/2 inch pieces
- 1 tablespoon all purpose flour, for tossing the rhubarb
- 1/2 cup unsalted butter, for the sauce
- 3/4 cup granulated sugar, for the sauce
- 1/2 cup heavy cream, for the sauce
- 1 teaspoon vanilla extract, for the sauce
All purpose flour. Gives the cake its structure. Toss the rhubarb in a spoonful so the pieces stay suspended in the batter.
Butter. Softened butter creams with the sugar for a tender crumb. Use unsalted so you control the salt.
Rhubarb. Use the stalks only, since the leaves are toxic. Chop them into small, even pieces.
Milk. Adds moisture so the rich butter batter stays soft.
Baking powder. Three teaspoons give enough lift for 3 cups of flour.
How to Make Rhubarb Cake with Butter Sauce
1. Prepare the pans Heat the oven to 350 degrees F. Grease and flour two 9 inch round cake pans.
2. Cream the butter and sugar Beat the butter and 1 1/2 cups sugar for 3 to 4 minutes until pale and fluffy.
3. Add the eggs Beat in the eggs one at a time, then stir in the vanilla.
4. Mix the dry ingredients Whisk the 3 cups flour, baking powder, and salt in a separate bowl.
5. Combine the batter Add the dry mix to the butter mixture in three parts, alternating with the milk, and stir until just combined.
6. Fold in the rhubarb Toss the rhubarb with 1 tablespoon flour and fold it gently into the batter.
7. Bake the layers Divide the batter between the pans, smooth the tops, and bake for 28 to 32 minutes until a toothpick comes out clean.
8. Cool the layers Cool in the pans for 10 minutes, then move to wire racks and cool completely, about 1 hour.
9. Make the sauce Melt the butter in a saucepan over medium heat, whisk in the sugar and cream, and simmer gently for 4 to 5 minutes, then stir in the vanilla.
10. Finish the cake Stack the layers on a plate and spoon the warm sauce over the top, letting it run down the sides.
How to Serve Rhubarb Cake with Butter Sauce
Serve slices warm with extra butter sauce spooned over the plate. Pair them with baked cinnamon rice pudding and fresh fruit pavlova for a spring dessert table. A slice also works next to homemade strawberry cake or sour cream coffee cake at brunch. A spoonful of whipped cream balances the tart fruit.
How to Store and Reheat Rhubarb Cake with Butter Sauce
Cover the cake and refrigerate it for up to 4 days, since the butter sauce contains cream. Warm slices briefly in the microwave to soften the sauce. Freeze unsauced slices wrapped tightly for up to 3 months and thaw overnight in the refrigerator. Make a fresh batch of sauce for serving.
Tips and Variations for Rhubarb Cake with Butter Sauce
Use stalks only. Rhubarb leaves are toxic, so trim them off and discard them.
Chop evenly. Pieces about 1/2 inch wide cook through in the same time as the cake.
Soften the butter properly. It should dent easily but not look greasy, since cold butter makes a lumpy batter.
Do not overmix. Stop stirring once the flour disappears for a tender crumb.
Watch the sauce. Keep the heat gentle and stir often so the cream does not boil over.
Skip the raw batter. The batter contains raw eggs and flour, so do not taste it.
Flag the allergens. The cake contains wheat, eggs, and dairy, so label it for guests.
Store it safely. For general advice on cooling and storing baked goods with dairy, see the Purdue Extension guide to storing leftovers.
Frequently Asked Questions About Rhubarb Cake with Butter Sauce
Can I use frozen rhubarb in rhubarb cake with butter sauce?
Yes. Chop it while still frozen, toss it with the flour, and fold it in without thawing so it does not bleed into the batter.
Can I bake rhubarb cake with butter sauce in a 9×13 pan?
Yes. Bake the batter in a greased 9×13 pan for 40 to 45 minutes, until a toothpick comes out clean.
How do I store rhubarb cake with butter sauce?
Refrigerate it covered for up to 4 days. Freeze unsauced slices for up to 3 months.
Can I make the butter sauce ahead?
Yes. Refrigerate it for up to 4 days and rewarm it gently on the stove, whisking until smooth.
Can I use half milk and half cream in the sauce?
Yes, though the sauce will be thinner. Simmer it 1 to 2 minutes longer to thicken it.
Rhubarb Cake with Butter Sauce
Equipment
- Two 9 inch round cake pans
- Electric mixer
- Saucepan
- Wire rack
Ingredients
Main Ingredients
- 3 cup all purpose flour
- 1 ½ cup granulated sugar
- 1 cup unsalted butter softened
- 4 large eggs room temperature
- 1 cup whole milk
- 3 tsp baking powder
- ½ tsp kosher salt
- 1 tsp vanilla extract for the cake
- 2 cup chopped rhubarb stalks only, in 1/2 inch pieces
- 1 tbsp all purpose flour for tossing the rhubarb
- ½ cup unsalted butter for the sauce
- ¾ cup granulated sugar for the sauce
- ½ cup heavy cream for the sauce
- 1 tsp vanilla extract for the sauce
Instructions
Cooking
- Prep. Set the oven to 350 degrees F and grease and flour two 9 inch pans.
- Cream. Beat the butter and sugar for 3 to 4 minutes, then beat in the eggs one at a time with the vanilla.
- Mix. Alternate the whisked flour, baking powder, and salt with the milk, stirring until just combined.
- Fold and bake. Fold in the floured rhubarb, divide between the pans, and bake for 28 to 32 minutes.
- Cool. Cool in the pans for 10 minutes, then cool completely on racks.
- Make the sauce. Melt the butter, whisk in the sugar and cream, simmer for 4 to 5 minutes, stir in the vanilla, and spoon over the cake.
