Name: Rhubarb Cake with Butter Sauce
Prep time: 15 min
Cook time: 50 min
Total time: 1 h 5 min
Cuisine: American
Ingredients: 2 cups chopped fresh rhubarb; 2 cups all-purpose flour; 1 teaspoon baking soda; 1/2 teaspoon salt; 1 1/2 cups granulated sugar; 1 large egg; 1 cup buttermilk; 1 teaspoon vanilla extract; 1/2 cup unsalted butter, melted; For the butter sauce:; 1/2 cup unsalted butter; 1/2 cup heavy cream; 1 cup granulated sugar; 1 teaspoon vanilla extract

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This rhubarb cake with butter sauce is the perfect blend of sweet and tangy flavors. Moist and tender, the cake is filled with fresh rhubarb that balances beautifully with the rich, velvety butter sauce poured over the top. It’s a comforting dessert that’s simple to make and guaranteed to impress.

Why You’ll Love This Recipe

I love how this rhubarb cake takes a classic spring ingredient and turns it into something so cozy and indulgent. The tartness of the rhubarb is mellowed by the buttery richness of the sauce, making every bite warm and satisfying. It’s easy to make with everyday ingredients, and the sauce adds an extra layer of decadence that takes it over the top. This is one of those recipes I keep coming back to whenever rhubarb is in season. Rhubarb Cake with Butter Sauce

Ingredients

(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)

Chopped fresh rhubarb
All-purpose flour
Baking soda
Salt
Granulated sugar
Egg
Buttermilk
Vanilla extract
Unsalted butter

For the butter sauce:

Unsalted butter
Heavy cream
Granulated sugar
Vanilla extract

Directions

I start by preheating the oven and greasing a baking dish.
In a mixing bowl, I whisk together the flour, baking soda, and salt.
In a separate bowl, I cream the sugar and egg until light and fluffy, then add the buttermilk and vanilla.
I gradually combine the wet and dry ingredients, stirring just until blended.
I fold in the chopped rhubarb, pour the batter into the prepared pan, and bake until the top is golden and a toothpick comes out clean.
While the cake is baking, I make the butter sauce by melting the butter with cream and sugar, then finishing with a splash of vanilla.
Once the cake is done, I serve each slice warm with the luscious butter sauce drizzled generously on top.

Servings and timing

This recipe makes about 12 servings and takes around 15 minutes to prepare, with a bake time of 45–50 minutes. The butter sauce takes just 5–7 minutes to cook while the cake is in the oven.

Variations

When I want to switch things up, I sometimes use half rhubarb and half strawberries for a slightly sweeter twist. If buttermilk isn’t on hand, I use a mix of milk and lemon juice or vinegar as a substitute. A sprinkle of cinnamon or nutmeg in the batter also adds a warm spice note that pairs beautifully with the rhubarb and butter sauce.

Storage/reheating

I store leftovers in an airtight container in the fridge for up to 4 days. When I’m ready to reheat, I warm individual slices in the microwave for about 20–30 seconds and gently reheat the butter sauce on the stovetop or microwave, stirring until smooth. The sauce can thicken when chilled, so I sometimes add a splash of cream to loosen it up. Rhubarb Cake with Butter Sauce

FAQs

How tart is the rhubarb in this cake?

Rhubarb has a naturally tangy flavor, but in this cake, I find it balances perfectly with the sweet batter and rich butter sauce. It’s not overly sour, just pleasantly sharp.

Can I use frozen rhubarb?

Yes, I’ve made this with frozen rhubarb. I just thaw and drain it well before adding to the batter to avoid extra moisture.

What’s a good substitute for buttermilk?

If I don’t have buttermilk, I mix 1 tablespoon of lemon juice or vinegar with 1 cup of milk and let it sit for 5–10 minutes. It works great in this recipe.

Can I make this cake ahead of time?

Absolutely. I often bake the cake a day in advance and store it covered. I make the butter sauce fresh or reheat it just before serving for the best texture.

Do I have to serve the cake warm?

While I prefer it warm, especially with the sauce, I’ve also enjoyed it at room temperature. It’s still delicious, though the sauce soaks in a bit more when warm.

Conclusion

This rhubarb cake with butter sauce is one of those comforting desserts that never fails to please. It’s easy to prepare, full of seasonal flavor, and that buttery sauce makes it feel like something truly special. Whether I’m baking it for a spring get-together or just a cozy night in, it always hits the spot.