Rhubarb Cake with Sauce

This tangy-sweet rhubarb cake topped with a luscious butter sauce transforms humble garden rhubarb into a dessert that's both rustic and elegant. Perfect for spring gatherings or whenever you find those ruby-red stalks at the market.

I discovered this recipe during my first spring in our new home when the rhubarb patch in the backyard exploded with stalks. After experimenting with several recipes, this cake became our family favorite, especially when my daughter declared it even better than her birthday cake.

Ingredients

• For the cake
• All purpose flour: Provides the perfect structure while keeping the crumb tender
• Baking powder: Gives just the right amount of lift without being overly cakey
• Salt: Enhances all the flavors and balances the sweetness
• Granulated sugar: Sweetens the cake and helps to tame the tartness of rhubarb
• Unsalted butter: Adds richness and moisture look for European style for extra flavor
• Egg: Binds everything together and adds structure
• Vanilla extract: Provides warmth and depth of flavor
• Milk: Creates a moist tender crumb whole milk works best
• Fresh rhubarb: Brings tangy brightness choose stalks that are firm and bright in color
• For the butter sauce
• Unsalted butter: Forms the luxurious base of this sauce
• Granulated sugar: Dissolves into the butter creating a caramel like sweetness
• Heavy cream: Adds silky richness and prevents crystallization
• Vanilla extract: Rounds out the flavors with subtle aromatic notes

Step-by-Step Instructions

Prepare Your Baking Pan:

Preheat your oven to 350°F and thoroughly grease your 9inch square baking pan making sure to get into all corners to prevent sticking

Mix Dry Ingredients:

Combine flour baking powder and salt in a medium bowl with a whisk to ensure even distribution of leavening agents throughout the batter

Cream Butter and Sugar:

Beat the butter and sugar together until the mixture becomes noticeably lighter in color and fluffy in texture about 3 to 4 minutes this incorporates air for a lighter cake

Add Wet Ingredients:

Mix in the egg and vanilla extract until fully incorporated the mixture might look slightly curdled but will come together when you add the flour

Combine Wet and Dry Ingredients:

Add the flour mixture in three portions alternating with two additions of milk beginning and ending with flour this prevents overmixing and keeps the cake tender

Fold in Rhubarb:

Gently fold the chopped rhubarb pieces into the batter using a spatula with a light hand to maintain as much air in the batter as possible

Bake the Cake:

Spread the batter evenly in your prepared pan and bake for 45 to 50 minutes until the top is golden brown and a toothpick inserted in the center comes out with just a few moist crumbs

Prepare Butter Sauce:

While the cake bakes combine butter sugar and heavy cream in a saucepan over medium heat stirring constantly until the mixture becomes smooth and slightly thickened about 5 minutes

Finish the Sauce:

Remove the sauce from heat and stir in vanilla extract allowing the sauce to cool slightly which will thicken it further to a perfect pouring consistency

Serve Warm Cake:

Allow the cake to cool for about 10 minutes then cut into squares and drizzle generously with warm butter sauce letting it soak slightly into the cake before serving

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The butter sauce is what truly transforms this dessert from a simple fruit cake to something extraordinary. I learned this recipe from my grandmother who insisted that the sauce should always be warm when poured over the cake. She would prepare extra sauce and keep it in a little pitcher so everyone could add more to their slices – a tradition I continue today.

Seasonal Variations

While classic rhubarb is traditional in spring, this versatile cake base works beautifully with other fruits throughout the year. In summer, try substituting the same amount of blueberries, raspberries, or sliced strawberries. For fall, diced apples or pears with a sprinkle of cinnamon make a wonderful adaptation. Just remember that juicier fruits might require an extra tablespoon or two of flour to absorb excess moisture.

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Storage Tips

The cake itself keeps beautifully at room temperature for up to three days when stored in an airtight container. If you need to keep it longer, refrigerate for up to a week, though the texture is best in the first few days. The butter sauce should be stored separately in the refrigerator where it will solidify. To serve leftover cake, gently reheat individual portions in the microwave for about 20 seconds, and warm the sauce in a small saucepan or microwave until pourable again.

Rhubarb Selection Guide

For the best flavor in this cake, look for rhubarb stalks that are firm, crisp and bright in color—typically a vibrant pink to deep red. While color doesn't necessarily indicate ripeness, redder stalks tend to be sweeter than green ones. Avoid stalks that are limp, bruised or have dried ends. Remember that rhubarb leaves contain oxalic acid and are toxic, so always discard them completely. If using garden rhubarb, harvest stalks that are at least 10 inches long for best flavor and texture.

Frequently Asked Questions

→ How do I ensure the cake stays moist?

Use fresh rhubarb, and ensure you follow the alternating method of adding wet and dry ingredients. Avoid overmixing the batter.

→ Can I use frozen rhubarb?

Yes, but thaw and drain the frozen rhubarb thoroughly to prevent excess liquid from affecting the texture of the cake.

→ What can I substitute for heavy cream in the butter sauce?

You can use half-and-half or whole milk, though the sauce may be slightly less rich and creamy.

→ How should I store the cake and sauce?

Store the cake in an airtight container at room temperature for up to 2 days. Refrigerate any leftover butter sauce in a sealed container for up to a week.

→ Can I adjust the sweetness of the butter sauce?

Absolutely. Use less sugar and taste as you go while preparing the sauce to ensure it matches your preference.