Cocoa Layer Cake with Chocolate Buttercream

This dependable cocoa cake uses a thin hot-water batter for moist layers and a simple whipped chocolate buttercream for a clean, classic finish.

135 min

12 slices

Ingredients

2 cups all-purpose flour

1 3/4 cups granulated sugar

3/4 cup unsweetened cocoa powder

1 1/2 tsp baking powder

1 1/2 tsp baking soda

1 tsp fine salt

2 large eggs, at room temperature

1 cup whole milk

1/2 cup neutral oil

1 cup boiling water

1 1/2 cups unsalted butter, powdered sugar, cocoa powder, and vanilla extract

Two 8-inch round cake pans · Parchment paper · Large mixing bowl · Whisk · Wire rack · Electric mixer · Offset spatula · Cake plate

Make ahead

Bake and cool layers one day ahead; wrap airtight at room temperature, then frost before serving.

Clean slices

Wipe and warm the knife between cuts for neat slices through the soft frosting.

01. Grease, line, and cocoa-dust both pans so the layers release cleanly.

02. Whisk flour, sugar, cocoa, leaveners, and salt until even.

03. Whisk eggs, milk, and oil into the dry ingredients only until smooth.

04. Whisk in boiling water, then stop as soon as the batter is glossy.

05. Divide batter between pans and bake until the centers spring back and a tester has moist crumbs.

06. Cool layers completely on a rack before frosting to keep the cake stable.

07. Beat butter with powdered sugar, cocoa, vanilla, and milk until fluffy.

08. Fill the cake, stack it level, and spread an even coat over the top and sides.

09. Let the frosting set briefly, then slice with a warm dry knife.