Preheat oven to 350 degrees. Grease and flour 2 round 9-inch cake pans.
For the cake, put flour, sugar, cocoa, baking powder, baking soda and salt in a bowl and mix well.
In a stand mixer, mix the buttermilk, oil, eggs, vanilla together. Slowly add in the mix of dry ingredients while the mixer is on low. Add the coffee and make sure everything is combined. The batter will be very thin.
Pour the batter into the prepared pans and bake for about 25 minutes or until a toothpick inserted in the middle comes out clean.
Allow the cakes to cool on a wire rack for 10 minutes. Turn the cakes out onto a cooling rack.