Preheat the oven to 350°F. Grease and flour three 8" or 9" round cake pans.
In a large bowl, whisk together the sugar, flour, cocoa powder, baking soda, baking powder, and salt until evenly combined.
Add the vanilla, eggs, buttermilk, and oil. Stir until combined.
Stir in the hot coffee quickly to ensure it's evenly distributed. The batter will be very thin.
Pour the batter into the prepared cake pans. Bake for 30-40 minutes, or until a toothpick comes out clean.
Let the cakes cool completely.