Preheat oven to 350 degrees F (175 degrees C). Grease and flour two 9-inch round cake pans.
In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt. In a separate bowl, whisk together the cocoa powder, oil, buttermilk, eggs, and vanilla extract. Slowly add the wet ingredients to the dry ingredients and whisk until just combined.
Slowly add the hot espresso or coffee and whisk until just combined. Pour the batter into the prepared pans and bake for 30 minutes, or until a toothpick inserted into the center comes out clean.
Remove from the oven and let cool for 10 minutes, then turn out onto a wire rack to cool completely.
To make the buttercream, cream the butter in a large bowl with an electric mixer until light and fluffy. Slowly add the confectioners’ sugar and cocoa powder and mix until combined. Add the vanilla extract and heavy cream or milk and mix until light and fluffy.
To assemble the cake, place one layer on a cake plate and spread with a layer of buttercream. Top with the second layer and spread the top and sides with the remaining buttercream.
Interesting Facts
The traditional American chocolate layer cake is a combination of chocolate cake and chocolate buttercream.
A moist chocolate layer cake is the perfect dessert for any occasion.
Adding espresso or coffee to the cake batter intensifies and deepens the chocolate flavor.