Chocolate Buttermilk Cake with Pecan Frosting
A rich, fudgy sheet cake with a glossy chocolate-pecan frosting. Buttermilk adds subtle tang to balance the cocoa intensity, while toasted pecans provide textural contrast. The frosting is poured warm over the hot cake, creating a set glaze. Ideal for potlucks, casual gatherings, or when you need a crowd-pleasing dessert without fussy decoration.
Ingredients
- 1 cup butter, softened
- ⅓ cup unsweetened cocoa powder, sifted if lumpy
- 1 cup water, room temperature
- ½ cup buttermilk, room temperature
- 2 large eggs, room temperature
- 1 teaspoon baking soda
- 1 teaspoon vanilla extract
- 2 cups sugar, granulated
- 2 cups all-purpose flourcake flour0.875 cup per cupflours
- ¼ teaspoon salt
- ¼ cup unsweetened cocoa powder, sifted if lumpy
- ⅓ cup buttermilk, room temperature
- 1 16-ounce package confectioners' sugar, sifted
- ½ cup pecans, toasted and choppedwalnuts or almonds1:1nutsFull guide →
Instructions
- 1
Preheat oven to 350 degrees and grease a 9x13-inch pan.
- 2
Combine butter, cocoa, and water in a small saucepan. Heat over low heat, stirring constantly, until butter melts completely. Cut butter into pieces to speed melting if needed. Remove from heat.
- 3
Using an electric mixer, beat buttermilk, eggs, baking soda, and vanilla extract until smooth.
- 4
Gradually add melted butter mixture to buttermilk mixture, beating until combined.
- 5
In a medium bowl, whisk together sugar, flour, and salt. Add to wet ingredients and beat until blended.
- 6
Pour batter into prepared pan. Bake 30 to 35 minutes, until set in the middle.
- 7
While cake bakes, make frosting: combine butter, cocoa, and buttermilk in a medium saucepan. Heat over medium heat, stirring constantly, until smooth.
- 8
Remove from heat and stir in confectioners' sugar, vanilla, and pecans.
- 9
Pour frosting over cake while still warm. Allow frosting to cool and set before slicing.
Tips
Cutting butter into smaller pieces before heating speeds melting and ensures even mixing with cocoa and water.
Pour frosting over the cake while both are still warm so it sets into a smooth, glossy layer.
Toast pecans yourself for maximum flavor; store-bought toasted varieties lose potency over time.
Good to Know
Cover and store at room temperature up to 3 days, or refrigerate up to 5 days. Frosting may soften slightly when refrigerated.
Bake cake 1 day ahead; cool completely, wrap, and store. Make frosting fresh and pour while warm, or reheat gently before pouring.
Serve at room temperature or slightly warm. Pairs well with coffee, milk, or vanilla ice cream.
Common Mistakes
Do not skip sifting cocoa powder to avoid lumps in batter and frosting.
Do not let butter-cocoa-water mixture boil to avoid scorching cocoa and creating a bitter flavor.
Do not pour frosting over a completely cooled cake to avoid it sliding off or not setting properly.
Substitutions
Dairy-Free Swaps
General Alternatives
FAQ
Can I make this cake in a different pan size?
Yes. Adjust baking time: 8-inch round pans require 35-40 minutes; 9-inch rounds require 30-35 minutes. A 8x8-inch square will bake faster, 25-30 minutes. Check doneness by inserting a toothpick in the center.
What if I don't have buttermilk?
Mix 1 tablespoon lemon juice or vinegar with regular milk and let sit 5 minutes. Use 1:1 as a substitute. Alternatively, use plain yogurt thinned slightly with milk for similar tang and moisture.
How long can I keep this cake?
Covered at room temperature, 3 days. Refrigerated, up to 5 days. Frosting may soften when chilled. Freezing the unfrosted cake works well; freeze up to 3 months, then thaw before frosting.