Heat oven to 350 degrees. Grease and flour one 13x9x2 inch pan. In a large mixing bowl, blend the sugar, flour, cocoa, baking soda, baking powder, and salt. Add the coffee, buttermilk, oil, eggs, and vanilla; beat on medium speed for 2 minutes. (batter will be thin) Pour into prepared pan. Bake 30-40 minutes or until wooded toothpick inserted in center comes out clean. Either, cool 10 minutes and remove cake from pan to wire rack to cool completely. Or, cool the cake completely in the pan before icing it.
Butter Cream Mocha Icing.
In a mixing bowl, cream the softened butter and Crisco until well blended. Add the powdered sugar, cocoa, vanilla, and milk mixture. Mix the milk into the coffee; add to mixture. Beat for 3-4 minutes until smooth and creamy. If icing seems a little too thick, add a bit more coffee or milk.