Step 1

Preheat the oven to 350 degrees Fahrenheit. Grease 2 (9-inch) round pans with non-stick spray or butter, and lightly coat them with flour.

Step 2

Add the sugar to a large bowl. Sift in the flour, cocoa powder, baking powder, baking soda, espresso powder, and salt.

Step 3

Make a well in the center of the dry ingredients. To it, pour in the eggs, milk, oil, and vanilla. Beat the ingredients just until well combined. Mix in the boiling water.

Step 4

Pour the batter evenly into the prepared pans. Bake for 30 to 35 minutes, or until a toothpick inserted into the center comes out clean.

Step 5

Allow the cakes to cool in the pans for 10 minutes, and then flip them over onto a wire rack to cool completely.

Step 6

Meanwhile, make the chocolate buttercream frosting. Beat the softened butter with an electric mixer at medium speed until it's light and fluffy.

Step 7

While continuously beating, gradually add the sifted powdered sugar and cocoa powder until it's creamy. Add the cooled melted chocolate and mix until smooth.

Step 8

Pipe or spread 1/3 of the frosting over one cake. Place the second cake on top, and frost the top and sides with the remaining frosting. Chill chocolate cake before serving. Slice and enjoy!