Rhubarb Cake with Butter Sauce is an old-fashioned dessert that combines tangy rhubarb with sweet butter sauce for the ultimate spring treat. This simple one-bowl cake bakes up tender and moist in a 9×13 pan. What makes this cake special is how the rich butter sauce transforms the tangy rhubarb into something magical. The sweet cream sauce balances the tart rhubarb perfectly.
Why You’ll Love This
- Tangy rhubarb becomes sweet perfection with butter sauce
- One-bowl mixing means easy cleanup
- No eggs required, so it’s super simple
- Perfect for potlucks in a 9×13 pan
- Great way to use up spring rhubarb
Rhubarb Cake with Butter Sauce
- Total Time: 2 hours
Description
Old-fashioned rhubarb cake with tangy rhubarb and sweet butter sauce, baked in a 9×13 pan for easy serving
Ingredients
For the Cake:
4 cups all-purpose flour
2 cups granulated sugar
4 teaspoons baking powder
1/2 teaspoon salt
4 cups rhubarb, diced
2 cups milk
6 tablespoons butter, melted
For the Butter Sauce:
1/2 cup butter (1 stick)
1 cup granulated sugar
3/4 cup heavy cream
Instructions
1. Preheat your oven to 350°F. Grease a 9×13 inch baking pan well with butter or cooking spray.
2. In your large bowl, whisk together flour, sugar, baking powder, and salt until evenly combined.
3. Add the diced rhubarb, milk, and melted butter to your dry ingredients. Stir gently until just combined. The batter will be thick.
4. Pour the batter into your prepared pan and spread evenly. Bake for 45 minutes or until a toothpick inserted in the center comes out clean. The top should be golden brown.
5. While the cake cools, combine butter, sugar, and heavy cream in a saucepan. Bring to a boil over medium heat, stirring frequently. Boil for 1 minute, stirring constantly. Remove from heat.
6. Cut the cake into squares and serve with a generous pour of warm butter sauce over each piece.
Notes
Fresh or frozen rhubarb works – thaw and drain frozen rhubarb first.
Don’t squeeze liquid from thawed rhubarb, just drain naturally.
Cut rhubarb into 1/2 inch pieces for even distribution.
Stir the sauce constantly during the 1-minute boil to prevent scorching.
Let cake cool 15 minutes before cutting.
Add 1 teaspoon vanilla to butter sauce for extra flavor.
This recipe is naturally egg-free.
Store covered at room temperature for up to 2 days.
Refrigerate for up to 5 days or freeze without sauce for up to 3 months.
- Prep Time: 15 minutes
- Cook Time: 45 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American
Ingredients
For the Cake:
- 4 cups all-purpose flour
- 2 cups granulated sugar
- 4 teaspoons baking powder
- 1/2 teaspoon salt
- 4 cups rhubarb, diced
- 2 cups milk
- 6 tablespoons butter, melted
For the Butter Sauce:
- 1/2 cup butter (1 stick)
- 1 cup granulated sugar
- 3/4 cup heavy cream
Fresh or frozen rhubarb works perfectly – just thaw and drain frozen rhubarb first.
Why These Ingredients Work
Diced rhubarb creates tart pockets throughout the cake that balance the sweetness. The pieces soften during baking but hold their shape for texture.
No eggs makes this cake especially tender and easy to mix. The milk and baking powder create the rise you need without eggs.
Heavy cream in the sauce creates that luxurious, pourable consistency. It’s rich enough to soak into the cake but not so thick it just sits on top.
Simple ingredients mean you can make this anytime without a special trip to the store. Flour, sugar, butter, milk – that’s it.
Tools Needed
- 9×13 inch baking pan
- Large mixing bowl
- Whisk
- Heavy saucepan for butter sauce
- Measuring cups and spoons
How To Make Rhubarb Cake with Butter Sauce
Step 1: Prep Your Pan
Preheat your oven to 350°F. Grease a 9×13 inch baking pan well with butter or cooking spray. Make sure every corner is greased so the cake releases easily after baking.
Step 2: Mix the Dry Ingredients
In your large bowl, whisk together flour, sugar, baking powder, and salt until evenly combined. These dry ingredients form the base of your tender cake.
Make sure there are no lumps of baking powder hiding in there.
Step 3: Add Wet Ingredients and Rhubarb
Add the diced rhubarb, milk, and melted butter to your dry ingredients. Stir gently until just combined. The batter will be thick and that’s perfect. Don’t overmix or your cake will be tough.
Step 4: Bake Until Golden
Pour the batter into your prepared pan and spread evenly. Bake for 45 minutes or until a toothpick inserted in the center comes out clean. The top should be golden brown and the cake should spring back when lightly touched.
Step 5: Make the Magic Butter Sauce
While the cake cools, combine butter, sugar, and heavy cream in a saucepan. Bring to a boil over medium heat, stirring frequently. Boil for 1 minute, stirring constantly. Remove from heat and let cool slightly before serving.
Step 6: Serve and Enjoy
Cut the cake into squares and serve with a generous pour of warm butter sauce over each piece. The sauce seeps into the cake creating pure heaven. You can reheat the sauce gently if it thickens too much while sitting.
You Must Know
- If using frozen rhubarb, thaw it completely and drain excess liquid before using
- Don’t skip the 1-minute boil for the sauce or it won’t thicken properly
- Serve the cake warm or at room temperature, but the sauce should always be warm
Amelia’s Secret: Add a teaspoon of vanilla extract to your butter sauce right after you take it off the heat. That little touch of vanilla makes the sauce taste like liquid heaven.
Pro Tips and Mistakes to Avoid
Cut rhubarb into small dice. Pieces should be about 1/2 inch so they distribute evenly and bake through properly.
Don’t overbake the cake. It should be just done when the toothpick comes out clean. Overbaking makes it dry, and the butter sauce can’t fix that.
Stir the sauce constantly during the boil. Cream and sugar can scorch quickly on the bottom of the pan if you walk away.
Let the cake cool slightly before cutting. If you cut it hot, it falls apart. Give it 15 minutes to set up.
Flavor Variations
Strawberry Rhubarb: Replace 1 cup of rhubarb with 1 cup diced fresh strawberries. Classic combination that everyone loves.
Orange Rhubarb: Add 1 tablespoon orange zest to the batter and 1 teaspoon to the butter sauce for bright citrus notes.
Ginger Spice: Add 1 teaspoon ground ginger and 1/2 teaspoon cardamom to the dry ingredients for warm spice flavor.
Nutty Topping: Sprinkle the top with sliced almonds before baking for extra crunch and visual appeal.
Make-Ahead Instructions
Bake Ahead: Make the cake up to 2 days in advance and store covered at room temperature. Make the butter sauce fresh before serving.
Freezing: Freeze the cake without sauce for up to 3 months. Wrap tightly in plastic wrap and foil. Thaw overnight and make fresh butter sauce.
Serving Suggestions
Serve warm with vanilla ice cream and extra butter sauce drizzled over everything. The cold ice cream melting into warm sauce is perfection.
Top with freshly whipped cream for a lighter option that still feels indulgent.
Pair with coffee or tea for an afternoon treat that feels special but wasn’t difficult to make.
How to Store
Room Temperature: Cover the cake and keep at room temperature for up to 2 days. Store extra butter sauce separately in the fridge.
Refrigerator: Store covered in the fridge for up to 5 days. The cake stays moist thanks to the rhubarb.
Reheating: Microwave individual portions for 20-30 seconds. Warm the butter sauce separately and pour over the heated cake.
Allergy Information
Contains: Wheat, dairy
Dairy-Free Option: Use dairy-free butter and plant-based milk in the cake. For the sauce, use coconut cream instead of heavy cream.
Gluten-Free Substitute: Use a 1:1 gluten-free flour blend. The texture will be slightly different but still delicious.
Egg-Free: This recipe is naturally egg-free, making it perfect for egg allergies.
Frequently Asked Questions
Can I use frozen rhubarb?
Yes! Thaw it completely and drain off excess liquid. Don’t squeeze it dry, just drain what naturally comes out during thawing.
Why is my cake dry?
You probably overbaked it. The toothpick should come out with a few moist crumbs, not completely clean. Also, make sure you’re pouring plenty of butter sauce over each piece.
Can I make this cake ahead for a party?
Absolutely! Bake the cake 1-2 days ahead. Make the butter sauce fresh on the day of your party and warm it before serving.
What if my rhubarb is really tart?
The butter sauce balances the tartness perfectly. If you’re worried, you can add an extra 1/4 cup sugar to the cake batter.
Can I halve this recipe?
Yes! Use an 8×8 or 9×9 pan and halve all the ingredients. Baking time will be about the same, maybe 5 minutes less.
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