One-Bowl Buttermilk Chocolate Cake

4.92 from 75 votes

One-Bowl Buttermilk Chocolate Cake

This old-fashioned buttermilk chocolate cake requires just one bowl and a whisk! You'll love the moist texture and the rich, fudgy icing. Perfect for birthdays, potlucks, or Sunday supper.

Course Dessert

Cuisine American

Keyword buttermilk chocolate cake, chocolate buttermilk cake, chocolate buttermilk cake with frosting, moist chocolate cake with buttermilk

Prep Time 30

Cook Time 35

Cooling Time 2

Total Time 3 5

Servings people

Calories 449kcal

Author Blair Lonergan

Equipment

9 x 13 baking pan

Ingredients

For the Cake:

2 cups all-purpose flour
2 cups granulated sugar
½ cup unsweetened cocoa powder
2 teaspoons baking soda
1 teaspoon baking powder
½ teaspoon salt
2 large eggs
1 cup vegetable oil
1 cup whole buttermilk, shaken
1 cup hot coffee (or hot water)

For the Chocolate Buttermilk Icing:

½ cup (1 stick) salted butter
⅔ cup unsweetened cocoa powder
3 cups confectioners' sugar, sifted
⅓ cup whole buttermilk, shaken
1 teaspoon vanilla extract

Instructions

Bake the Cake:

Preheat oven to 350°F. Grease and flour a 9 x 13-inch baking pan or line with parchment paper. Set aside.
In a large mixing bowl, whisk together flour, sugar, cocoa powder, baking soda, baking powder, and salt until combined and no cocoa clumps remain.
Add the eggs, oil, and buttermilk. Whisk well until combined.
Add the hot coffee (or hot water) and whisk until the batter is smooth. The batter will be thin.
Transfer the batter to the prepared baking pan. Tap gently on the counter to release air bubbles.
Bake for 30 to 35 minutes, or until a toothpick inserted in the center comes out clean or with just a few moist crumbs. Start checking at 30 minutes.
Cool completely in the pan before frosting.

Make the Icing:

Melt the butter in a saucepan over medium-low heat.
Whisk in the cocoa powder and cook over low heat for 2 minutes, stirring constantly. Do not let it boil.
Remove from the heat. Add the sifted powdered sugar and buttermilk, whisking until smooth.
Add the vanilla and whisk to combine. The icing should be glossy and spreadable. If too thick, add extra buttermilk one tablespoon at a time.
Spread the warm icing over the cooled cake. Let the icing set for 15 to 20 minutes before slicing and serving.

Notes

Use all-purpose flour, not cake flour. The cocoa powder already has a soft, dry texture. Cake flour combined with cocoa can result in a flimsy cake. All-purpose flour keeps it sturdy.
Use thick, whole buttermilk for the best richness, moisture, and flavor. Low-fat varieties won't give the same results.
Bring ingredients to room temperature before mixing. This helps them blend smoothly and prevents over-mixing.
Don't over-mix the batter. Too much mixing incorporates excess air (which deflates in the oven) and develops too much gluten (which makes the cake tough).
Don't over-bake. Start checking at 30 minutes. Even a minute or two too long can dry out the cake.
Sift the powdered sugar to avoid lumps in your frosting.
Spread the frosting while warm. It sets as it cools, so work quickly for even coverage.
Make it ahead. The cake tastes even better the next day as the flavors meld and the crumb becomes more tender.
For cupcakes: Fill lined tins two-thirds full. Bake at 350°F for 18 to 22 minutes. Makes about 24 cupcakes.
For a layer cake: Divide batter between two 8-inch or 9-inch round pans. Reduce baking time by about 5 minutes. Use a sturdier buttercream for stacking.
Buttermilk substitute: Mix 1 tablespoon lemon juice or white vinegar with 1 cup milk. Let sit 5 minutes before using.

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