Classic Chocolate Cake with Mocha Buttercream

I didn't just want to eat a piece of chocolate cake. I wanted to mix and sift and bake and frost and spend a few relaxed hours in the kitchen surrounded by butter and chocolate. It was bliss. This cake did not disappoint and it only got better as days went by. The cake and the mocha frosting are mild and light, not dense and rich as some chocolate on chocolate cakes tend to be. It makes it easier to eat larger slices of cake more frequently, if that's what you're into.

Chocolate Cake with Mocha Buttercream Frosting
Cake recipe courtesy of Nigella Lawson; Frosting recipe adapted from Guilty Kitchen

Cake
1 1/2 cups all-purpose flour
1 cup superfine sugar
1 teaspoon baking powder
1/2 teaspoon baking soda
1/3 cup good quality cocoa
1 1/2 sticks soft unsalted butter
2 large eggs
2 teaspoons vanilla extract
2/3 cup sour cream

Take the eggs and butter out of the refrigerator so that they can come up to room temperature. Preheat the oven to 350 degrees F. Put all the cake ingredients: flour, sugar, baking powder and soda, cocoa, butter, eggs, vanilla, and sour cream into a food processor and process until you have a smooth, thick batter. If you want to use a mixer, just mix the flour, sugar and leavening agents in a large bowl and beat in the soft butter until you have a combined and creamy mixture. Now whisk together the cocoa, sour cream, vanilla, and eggs and beat this into your bowl of mixture.

Divide this batter, using a rubber spatula to help you scrape and spread, into buttered tins. I used three 6-inch tins, which baked for about 20 minutes, but test the cake before removing from the oven. When done baking, move the cakes to a wire rack and let cool for 10 minutes before turning them out of their tins.

Mocha Buttercream Frosting
1 cup unsalted butter, room temperature
1 1/3 cups powdered sugar, sifted
2 teaspoons vanilla extract
1 1/2 teaspoons instant coffee or espresso
1/3 cup cocoa

In the bowl of a stand mixer or using a hand held mixer, beat butter until fluffy, about five minutes. In a small bowl, combine instant coffee or espresso powder with vanilla extract, stir until coffee granules completely dissolve. Set aside. With mixer on low, add half of powdered sugar to butter and mix until completely incorporated. Add vanilla and coffee to butter and beat in remaining sugar. Beat in cocoa until completely incorporated. Scrape down the sides of the bowl to ensure all ingredients are incorporated. Assemble and frost cooled cake using an offset spatula. Coat entire cake with thin layer of frosting, a crumb coat, and refrigerate for 30 minutes. Remove cake and add final layer of frosting over the crumb coat. Use the back of a spoon to achieve swirls on top of the cake.