Rhubarb Cake With Butter Sauce

Every spring, I look forward to rhubarb season, eagerly waiting for those bright red stalks to show up at the farmer’s market. My love for rhubarb started in my grandmother’s kitchen, where she turned this tart vegetable into the most comforting baked treats.

She had a way of balancing its sharpness with just the right amount of sweetness, and one of her best creations was this rhubarb cake with butter sauce. The soft, slightly tangy cake paired with a rich, velvety sauce was pure perfection—simple yet indulgent.

Now, every time I bake this cake, the scent alone brings back memories of those cozy afternoons. The way the rhubarb melts into the batter, adding pockets of juicy tartness, is what makes this cake so special.

And let’s talk about the butter sauce—it seeps into every bite, making it extra moist and impossible to resist. If you’ve never baked with rhubarb before, this is the perfect recipe to start with. It’s easy, foolproof, and a guaranteed hit at any gathering.

Plus, it’s one of those desserts that tastes even better the next day—assuming there’s any left!

Short Description

This rhubarb cake is a soft, moist treat packed with tangy rhubarb and topped with a decadent butter sauce. It’s easy to make, perfect for any occasion, and delivers the ultimate balance of sweet and tart flavors.

Key Ingredients

For the Cake:

• 2 cups diced rhubarb (fresh or frozen, thawed and drained)
• 1 cup granulated sugar
• ½ cup unsalted butter, softened
• 1 large egg
• 1 teaspoon vanilla extract
• 1 cup buttermilk
• 2 cups all-purpose flour
• 1 teaspoon baking soda
• ½ teaspoon salt

For the Butter Sauce:

• ½ cup unsalted butter
• 1 cup granulated sugar
• ½ cup heavy cream
• 1 teaspoon vanilla extract

Tools Needed

• 9×13-inch baking dish
• Mixing bowls
• Hand or stand mixer
• Whisk
• Spatula
• Saucepan
• Cooling rack

Step-by-Step Cooking Instructions

Step 1: Preheat the Oven

Preheat your oven to 350°F (175°C). Grease and flour a 9×13-inch baking dish to prevent sticking.

Step 2: Make the Cake Batter

In a large bowl, cream together the softened butter and sugar until light and fluffy. Beat in the egg and vanilla extract until fully incorporated.

In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the butter mixture, alternating with the buttermilk. Mix until just combined, being careful not to overmix.

Step 3: Fold in the Rhubarb

Gently fold the diced rhubarb into the batter, ensuring it’s evenly distributed.

Step 4: Bake the Cake

Spread the batter evenly into the prepared baking dish. Bake for 45-50 minutes, or until a toothpick inserted into the center comes out clean. Let the cake cool slightly in the pan.

Step 5: Make the Butter Sauce

While the cake is baking, melt the butter in a saucepan over medium heat. Add the sugar and heavy cream, stirring constantly until the sugar dissolves and the mixture thickens slightly. Remove from heat and stir in the vanilla extract.

Step 6: Serve

Cut warm slices of cake and drizzle generously with the warm butter sauce. Serve immediately for the best flavor and texture.

Why You’ll Love This Recipe

Perfectly Balanced Flavors: The tartness of rhubarb pairs beautifully with the sweet, buttery sauce.

Simple and Nostalgic: No complicated steps, just pure comfort food.

Moist and Tender Texture: Buttermilk keeps the cake soft and fluffy.

Great for Any Occasion: A wonderful dessert for family dinners, potlucks, or afternoon coffee breaks.

Mistakes to Avoid & Solutions

1. Overmixing the Batter

Overmixing can make the cake dense instead of light and tender. Mix only until the ingredients are combined.

2. Skipping the Buttermilk

Buttermilk adds moisture and tenderness. If you don’t have any, make a quick substitute by mixing 1 cup of milk with 1 tablespoon of vinegar or lemon juice.

3. Not Draining Frozen Rhubarb

Excess moisture from frozen rhubarb can make the cake soggy. Always drain it well before adding to the batter.

4. Undercooking the Butter Sauce

The sauce should be smooth and slightly thickened. If it’s grainy, the sugar may not have dissolved fully—keep stirring over low heat.

Serving and Pairing Suggestions

Best Served: Warm, drizzled with butter sauce.

Pair With: A scoop of vanilla ice cream or a dollop of freshly whipped cream.

Drink Pairings: Try it with a cup of coffee, chai tea, or a glass of cold milk.

Storage and Reheating Tips

Storing: Keep leftover cake in an airtight container at room temperature for up to 2 days or refrigerate for up to 5 days.

Reheating: Warm individual slices in the microwave for 15-20 seconds before serving. Reheat butter sauce gently on the stove or in the microwave.

FAQs

1. Can I use frozen rhubarb?
Yes! Just make sure to thaw and drain it well to avoid excess moisture.

2. What can I use instead of buttermilk?
Mix 1 cup of milk with 1 tablespoon of vinegar or lemon juice and let it sit for 5 minutes before using.

3. Can I make the butter sauce ahead of time?
Absolutely. Store it in the fridge for up to a week and reheat gently before serving.

4. How do I know when the cake is done?
Insert a toothpick into the center—if it comes out clean, it’s ready!

5. Can I add nuts or spices?
Yes! Chopped pecans or a touch of cinnamon can add extra warmth and texture.

Tips & Tricks

Use Fresh Rhubarb When Possible: Fresh rhubarb has a firmer texture and slightly brighter flavor than frozen.

Make Extra Butter Sauce: It’s so good, you’ll want extra for drizzling over pancakes or waffles.

For a Crunchy Topping: Sprinkle a little cinnamon sugar on top before baking for added texture.

Recipe Variations

Strawberry Rhubarb Cake: Replace half of the rhubarb with diced strawberries for a sweeter twist.

Gluten-Free Option: Swap all-purpose flour with a gluten-free 1:1 baking mix.

Spiced Rhubarb Cake: Add 1 teaspoon of cinnamon and ¼ teaspoon of nutmeg for a cozy spiced flavor.

Final Thoughts

Rhubarb cake with butter sauce is a recipe that never fails to impress, no matter how many times I make it. The balance of tart and sweet, the soft crumb, and that dreamy butter sauce all come together in the most comforting way. It’s one of those desserts that feels nostalgic yet timeless, the kind you’ll want to pass down through generations.

What I love most is how effortlessly it fits into any occasion. A slice with coffee in the morning? Perfect. Warm from the oven with a scoop of vanilla ice cream? Absolutely divine.

Even if rhubarb isn’t something you typically bake with, I promise this cake will change your mind. So, grab those ruby-red stalks and treat yourself to a dessert that’s as cozy as it is delicious.