Step 1

Preheat oven to 350 degrees. Grease three round baking pans and set aside. In a large bowl, stir together sugar, flour, cocoa, baking powder, baking soda, and salt. Add eggs, buttermilk, melted butter and vanilla extract; beat 2 minutes on medium speed. Stir in hot coffee.

Step 2

Pour batter evenly between the three pans and bake on middle rack of oven for 30 to 35 minutes, until toothpick inserted in center comes out clean. Cool completely on wire racks before frosting.

Step 3

Whip the room-temperature butter on medium speed. Shift to low and add cocoa powder slowly, spoonfuls at a time, until fully incorporated. Still on low, add in the powdered sugar (also one spoonful at a time), alternating with the milk, to achieve desired consistency and taste. Then, beat on medium speed until very light and fluffy, another 3-5 minutes. Add in more sugar if consistency is too thin.