Rhubarb Cake with Butter Sauce is a sweet and tangy dessert that’s perfectly moist and full of old-fashioned charm. I love how the tart rhubarb balances with the soft, tender cake—and once it’s soaked in that warm, buttery sauce, every bite becomes pure comfort.
Why You’ll Love This Recipe
I love how this cake transforms simple ingredients into something incredibly flavorful and nostalgic. The tartness of rhubarb adds brightness to the soft, sweet crumb, and the rich butter sauce poured over the top takes it to another level. It’s a great way to celebrate rhubarb season and makes for a beautiful dessert that feels both rustic and indulgent. Plus, it’s easy to make and perfect for potlucks, family dinners, or just because.
ingredients
(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)
For the cake:
all-purpose flour
baking soda
salt
granulated sugar
egg
buttermilk
vanilla extract
chopped fresh rhubarb
For the butter sauce:
unsalted butter
heavy cream or milk
granulated sugar
vanilla extract
directions
-
I preheat the oven to 350°F and grease a 9×13-inch baking dish.
-
In a large bowl, I whisk together the flour, baking soda, salt, and sugar.
-
In another bowl, I mix the egg, buttermilk, and vanilla extract.
-
I stir the wet ingredients into the dry ingredients until just combined, then fold in the chopped rhubarb.
-
I pour the batter into the prepared baking dish and spread it evenly.
-
I bake for 40–45 minutes, or until a toothpick inserted in the center comes out clean and the top is lightly golden.
-
While the cake is baking, I make the butter sauce by combining the butter, cream, and sugar in a small saucepan.
-
I bring the mixture to a gentle boil, stirring constantly, then remove from heat and stir in the vanilla extract.
-
I serve the warm cake with a generous spoonful (or two) of hot butter sauce over each slice.
Servings and timing
This recipe makes about 12 servings and takes roughly 1 hour total—15 minutes for prep and 40–45 minutes to bake, plus time to make the sauce.
Variations
Sometimes I mix in a handful of chopped strawberries with the rhubarb for a sweeter touch or sprinkle cinnamon or nutmeg into the batter for extra warmth. When I want a bit of crunch, I top the cake with a light brown sugar streusel before baking. The butter sauce can also be flavored with a splash of rum or almond extract for something a little different.
storage/reheating
I store the cake covered at room temperature for up to 2 days or in the fridge for up to 4. The butter sauce keeps in the fridge for a few days, and I reheat it gently on the stovetop or in the microwave before serving. The cake also freezes well—I wrap individual slices and freeze for up to 2 months.
FAQs
Can I use frozen rhubarb?
Yes, I use frozen rhubarb often—I just thaw it and drain any excess liquid before folding it into the batter.
Can I make this cake without buttermilk?
If I’m out of buttermilk, I mix 1 tablespoon of vinegar or lemon juice into 1 cup of milk and let it sit for 5 minutes as a quick substitute.
Is the butter sauce necessary?
Technically no, but I wouldn’t skip it. The sauce soaks into the cake and adds an incredible richness that really makes the dessert special.
Can I reduce the sugar?
Yes, I’ve cut back a little on the sugar in the cake and sauce and it still turns out great—just slightly less sweet.
What does rhubarb taste like?
Rhubarb is tart and slightly fruity—it softens beautifully in baking and pairs especially well with sweet and creamy elements like this butter sauce.
Conclusion
Rhubarb Cake with Butter Sauce is a cozy, satisfying dessert that brings together tart fruit, soft cake, and a rich, velvety topping. Whether I’m making it for a special occasion or simply craving something sweet and homey, this cake always feels like a treat straight from a farmhouse kitchen.
Print
Rhubarb Cake with Butter Sauce
- Prep Time: 15 minutes
- Cook Time: 45 minutes
- Total Time: 1 hour
- Yield: 12 servings
- Category: Dessert
- Method: Baking
- Cuisine: American
- Diet: Vegetarian
Description
Rhubarb Cake with Butter Sauce is a sweet-tart dessert with soft, moist crumb and a warm, velvety butter sauce that soaks into every bite—an old-fashioned treat perfect for spring and summer gatherings.
Ingredients
- 2 cups all-purpose flour
- 1 teaspoon baking soda
- 1/2 teaspoon salt
- 1 cup granulated sugar
- 1 large egg
- 1 cup buttermilk
- 1 teaspoon vanilla extract
- 2 cups chopped fresh rhubarb
- 1/2 cup unsalted butter (for sauce)
- 1/2 cup heavy cream or milk (for sauce)
- 1 cup granulated sugar (for sauce)
- 1 teaspoon vanilla extract (for sauce)
Instructions
- Preheat oven to 350°F (175°C) and grease a 9×13-inch baking dish.
- In a large bowl, whisk together flour, baking soda, salt, and sugar.
- In another bowl, mix egg, buttermilk, and vanilla extract.
- Combine wet and dry ingredients until just mixed, then fold in chopped rhubarb.
- Pour batter into the prepared pan and spread evenly.
- Bake for 40–45 minutes, or until a toothpick inserted in the center comes out clean.
- Meanwhile, make the butter sauce by heating butter, cream, and sugar in a saucepan over medium heat. Stir constantly until it comes to a gentle boil, then remove from heat and stir in vanilla.
- Serve cake warm with a generous spoonful of hot butter sauce over each slice.
Notes
- Use frozen rhubarb if fresh isn’t available—just thaw and drain first.
- Add strawberries, cinnamon, or nutmeg for flavor variations.
- Top with brown sugar streusel before baking for added texture.
- The butter sauce can be flavored with almond extract or a splash of rum.
- Wrap and freeze individual cake slices for up to 2 months.
Nutrition
- Serving Size: 1 slice with sauce
- Calories: 360
- Sugar: 33g
- Sodium: 180mg
- Fat: 17g
- Saturated Fat: 10g
- Unsaturated Fat: 6g
- Trans Fat: 0g
- Carbohydrates: 48g
- Fiber: 1g
- Protein: 4g
- Cholesterol: 60mg
Your email address will not be published. Required fields are marked *