1Preheat oven to 350°F. Line and grease two 8-inch round pans.
2Make the batter: Mix sugar, flour, cocoa, baking powder, baking soda, and salt. Add eggs, buttermilk, oil, and vanilla. Stir in hot coffee (batter will be thin).
3Bake for 30-35 minutes or until a toothpick comes out clean. Let cool completely.
4Make frosting: Mix butter and cocoa, then add powdered sugar, milk, and vanilla. Beat until smooth.
5Assemble and frost! Spread frosting between layers and over the top.