Texas Sheet Cake

2 cups sugar
2 cups flour
4 TBSP cocoa
1 tsp. baking soda
½ tsp. salt
2 sticks margarine
1 cup water
½ cup buttermilk
2 eggs
1 tsp. pure vanilla

Heat margarine, water, and cocoa in saucepan until boiling. Remove from heat and add sugar, flour, baking soda and salt; mix well. Add buttermilk, eggs, and vanilla, mix well. Pour batter into a greased 10x15 inch pan. Bake at 350 degrees for 20-25 minutes.