Old-Fashioned Rhubarb Cake with Butter Sauce

Rhubarb Cake with Butter Sauce is a classic spring dessert that transforms tart rhubarb into tender, moist cake topped with rich, sweet butter cream sauce. This simple one-bowl cake comes together quickly without eggs, making it incredibly easy for last-minute gatherings or potlucks.

Why You’ll Love This Recipe

• One-bowl mixing means minimal cleanup and maximum ease
• No eggs required, making it simple and allergy-friendly
• Uses fresh or frozen rhubarb so you can make it year-round
• Butter sauce turns simple cake into irresistible dessert
• Serves 15 people, perfect for potlucks, picnics, and family gatherings

Equipment Needed

• 9×13 inch baking pan
• Large mixing bowl
• Whisk
• Medium saucepan for sauce
• Measuring cups and spoons
• Spatula
• Toothpick for testing

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Ingredients

For the CAKE:

• 4 cups all-purpose flour
• 2 cups granulated sugar
• 4 tsp baking powder
• ½ tsp salt
• 4 cups rhubarb, diced (fresh or frozen)
• 2 cups milk
• 6 Tbsp butter, melted

For the BUTTER SAUCE:

• ½ cup (1 stick) butter
• 1 cup granulated sugar
• ¾ cup heavy cream

Ingredient Notes

Rhubarb should be cut into ½-inch pieces for even distribution throughout cake. Fresh rhubarb works beautifully in season, but frozen rhubarb makes this recipe accessible year-round. Thaw frozen rhubarb and drain excess liquid but don’t squeeze dry.

Milk provides moisture and tenderness in this eggless cake. Whole milk creates richest texture but 2 percent or even non-dairy milk works well. The milk combines with melted butter to create surprisingly tender crumb.

Butter sauce is pure indulgence with just three ingredients. Use real butter, not margarine, for proper flavor and texture. Heavy cream is essential – half-and-half or milk won’t create same rich, silky sauce.

Step-by-Step Instructions

Step 1: Preheat oven to 350°F

Preheat oven to 350°F. Grease 9×13 inch baking pan thoroughly, getting into all corners. You can also line with parchment paper for easiest release.

Step 2: In large bowl, whisk together flour, sugar, baking powder, and salt until evenly combined

In large bowl, whisk together flour, sugar, baking powder, and salt until evenly combined. This ensures baking powder distributes evenly for even rise.

Step 3: Add diced rhubarb to dry ingredients and toss to coat

Add diced rhubarb to dry ingredients and toss to coat. This prevents rhubarb from sinking to bottom and helps it distribute throughout cake.

Step 4: Pour in milk and melted butter

Pour in milk and melted butter. Stir gently until just combined – don’t overmix. Batter will be thick but pourable. Some small lumps are fine.

Step 5: Pour batter into prepared pan and spread evenly

Pour batter into prepared pan and spread evenly. Bake 45 minutes or until toothpick inserted in center comes out clean. Top should be golden brown.

Step 6: While cake bakes, make butter sauce

While cake bakes, make butter sauce. Combine butter, sugar, and heavy cream in heavy-bottomed saucepan. Bring to boil over medium heat, stirring frequently.

Step 7: Once boiling, continue cooking for exactly 1 minute while stirring constantly

Once boiling, continue cooking for exactly 1 minute while stirring constantly. Remove from heat and let cool slightly. Sauce will thicken as it cools.

Step 8: Remove cake from oven and cool for 10-15 minutes

Remove cake from oven and cool for 10-15 minutes. Pour warm butter sauce over warm cake, letting it soak in. Reserve some sauce for serving if desired.

Pro Tips & Cooking Hacks

• Don’t skip coating rhubarb in flour mixture – it prevents sinking
• Use toothpick test starting at 40 minutes to avoid overbaking
• Make sauce while cake bakes so both are warm when combining
• Cut rhubarb into uniform pieces for even distribution and baking
• Double the butter sauce because everyone always wants more
• Serve cake warm with extra sauce drizzled on each piece

Tips & Variations

Make cranberry version by substituting 4 cups fresh or frozen cranberries for rhubarb. This creates traditional Christmas dessert with same tangy-sweet balance. Cranberries and butter sauce are classic pairing.

Add vanilla extract or almond extract to cake batter for extra flavor dimension. One teaspoon of either enhances rhubarb’s natural tartness. Vanilla is more subtle while almond creates more distinctive flavor.

Create strawberry rhubarb cake by using 2 cups rhubarb and 2 cups sliced strawberries. The strawberries add sweetness and beautiful color. This combination is classic for good reason.

Serving Suggestions

Serve warm cake with generous drizzle of warm butter sauce. The contrast of tangy rhubarb and sweet, rich sauce is perfection. Add scoop of vanilla ice cream for ultimate comfort dessert experience.

Cut into squares and serve on dessert plates with fork. This cake is tender and moist, so it holds shape well. Dust with powdered sugar for pretty presentation at potlucks or dinner parties.

Common Mistakes

• Squeezing moisture out of thawed frozen rhubarb, which makes cake dry
• Overmixing batter after adding liquid, creating tough, dense cake
• Cutting rhubarb pieces too large, which creates uneven texture
• Overbaking cake until dry instead of stopping when just barely done
• Making sauce ahead and letting it get cold, preventing proper absorption
• Not greasing pan well enough, causing cake to stick

What to Serve With

Pair with hot coffee or tea for perfect afternoon treat. The butter sauce richness pairs beautifully with strong coffee. Earl Grey or English Breakfast tea complement rhubarb’s tartness nicely.

Serve as dessert after hearty spring dinner. This cake makes perfect ending to pot roast, roasted chicken, or pork chops. Light enough not to overwhelm after filling meal but satisfying enough to feel special.

Frequently Asked Questions

Can I use frozen rhubarb?

Yes! Thaw rhubarb first and let excess liquid drain off naturally. Don’t squeeze or press out moisture – just drain what naturally separates. Use exactly as you would fresh rhubarb.

Why is my cake dense and heavy?

Overmixing after adding liquids develops gluten and creates dense texture. Stir just until dry ingredients disappear. Also ensure baking powder is fresh for proper rise.

How do I store leftovers?

Cover cake tightly and store at room temperature for 2 days or refrigerate up to 5 days. Cake actually improves after day as sauce soaks in more. Warm individual pieces before serving.

Can I freeze this cake?

Yes! Freeze cake without sauce for up to 3 months. Wrap tightly in plastic wrap then aluminum foil. Thaw overnight in refrigerator and make fresh butter sauce before serving.

What can I substitute for rhubarb?

Fresh or frozen cranberries work perfectly with exact same measurements. Tart cherries or sour pie cherries also work well. Avoid sweet fruits as they don’t balance the butter sauce.