Preheat oven to 350 degrees F. Grease and flour two 9-inch round baking pans, in order to make 2 cake layers.
In a large bowl, stir together sugar, flour, cocoa powder, baking powder, baking soda, and salt. Add eggs, milk, oil, and vanilla. Beat all on medium speed with electric mixer for 2 minutes.
Stir in boiling, strong, hot coffee; batter will be thin.
Pour batter into prepared pans. Bake 30-35 minutes, or until a toothpick inserted near the center comes out clean.
Cool 10 minutes, then remove cake layers from pans to wire racks.
While cake is cooling, make the icing. To make icing, mix cream cheese, margarine, and vanilla extract. Add sugar and beat until creamy and smooth.
To finish cake, make sure the layers are completely cool. Take one round layer, place it on a serving plate, and top it with a layer of icing. Then place the other round layer on top, and ice the entire cake.