Mix sugar and flour together. Melt margarine, cocoa and water. Bring to boil add to flour mixture. Add buttermilk rest of ingredients. Mix well. Use pan 11 x 13 inch. Bake in preheated oven at 400 degrees for 20 minutes longer if it is soft on top don't over cook.
ICING:- Bring to boil and add 1 pound 10x sugar, 1 teaspoon vanilla mixture. Ice the cake as soon as it comes out of oven.