Combine flour, sugar, cocoa, soda, baking powder and salt in large mixer bowl. Add eggs, coffee, buttermilk or sour milk, oil and vanilla. Beat at medium speed for 2 minutes. (Batter will be thin!) Pour batter into a greased and floured 13 x 9 x 2 inch pan or two 9 inch cake pans. Bake at 350 degrees for 35 to 40 minutes for oblong pan or 30 to 35 minutes for layer pans. Cool. Frost with your favorite vanilla frosting, or CREAM CHEESE FROSTING listed below.
CREAM CHEESE FROSTING:
Combine all ingredients. Beat well. Spread on the completely cooled cake. (Frosting will beat up into more volume if cheese and butter are used directly out of the refrigerator.)