Chocolate Cake with Chocolate Buttercream

This rich, tender chocolate cake is easy to make and only requires one bowl. It bakes well in a variety of pan sizes so you can make this cake for any occasion.

4.56 from 152 votes

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Prep Time: 8

Cook Time: 30

Total Time: 38

Servings: to 24 servings depending on the baking pans used.

Calories: 410kcal

Author: Dahn Boquist

Ingredients

Chocolate Cake

1 cup unsweetened cocoa powder (80 grams)
1 cup boiling water or hot coffee (236 grams)
2 cups sugar (400 grams)
½ cup vegetable oil (100 grams)
1 cup sour cream (225 grams)
2 eggs
2 teaspoons vanilla extract
1-¾ cup all-purpose flour (210 grams)
1-½ teaspoons baking powder
1-½ teaspoons baking soda
1 teaspoon salt

Chocolate Buttercream Frosting

2 cups butter softened (452 grams)
6 to 7 cups powdered sugar* see notes (673 grams)
1 cup unsweetened cocoa powder (80 grams)
4 to 6 tablespoons milk or heavy cream
¼ teaspoon salt
2 teaspoons vanilla extract

Instructions

Easy Chocolate Cake:

Preheat the oven to 350°F. Spray three 8-inch cake pans with non-stick spray and line with parchment paper. (See the notes if you want to bake a different sized cake).
In a large mixing bowl, add the cocoa powder and boiling water or coffee. Whisk the chocolate mixture until smooth.
Add the sugar, vegetable oil, and sour cream and whisk until well blended.
Add the eggs and vanilla extract and whisk until the eggs are completely incorporated.
Sift the flour baking powder, baking soda, and salt over the batter. Whisk until there are no flour streaks.
Divide the batter among the baking pans and bake for 28 to 35 minutes. (See the notes if you use different sized pans).
Let the cakes cool for 5 to 10 minutes in the pans then run a knife around the edge of the pans to loosen the cake. Invert the cakes onto a cooling rack and let them cool completely before frosting them.

Chocolate Buttercream Frosting:

Place the butter in a mixing bowl and beat on medium speed for a couple of minutes until it is smooth and creamy.
Add 6 cups of the powdered sugar a cup at a time. Add the cocoa powder slowly and blend on medium speed until incorporated.
Add 4 tablespoons of the milk (or cream), salt, and vanilla extract. Increase the speed and beat for 2 to 3 minutes.
Stop the beater and check the consistency of the buttercream. Add additional powdered sugar if it is too thin or add 16extra milk if it is too thick.

Notes

Baking times for different sized pans:

Three 8-inch round cakes. Bake 28 to 35 minutes.
Two 9-inch round cake pans. Bake 28 to 35 minutes
13x9 pan = Bake 35 to 40 minutes
12 cup Bundt cake = Bake 50 to 55 minutes
Two 8-inch square cake pans. Bake 35 to 40 minutes
Standard-sized cupcake pans Bake 22 to 25 minutes. Makes 24 to 30 cupcakes.

For the buttercream:

Powdered sugar is also called icing sugar in some countries. It has a very fine, powdery texture that dissolves instantly. Do not use granulated sugar that has a sand-like texture.
When you add the powdered sugar and the cocoa powder to the mixer, just add a little at a time so the powder does not fly all over the kitchen.
The chocolate buttercream recipe makes about 4-1/2 cups which is enough buttercream to frost a 3 layer round cake. If you bake a 13x9 inch cake or a bundt cake, you will only need half of the buttercream recipe.