Marie's Chocolate Sheet Cake

Why I Love This Recipe
Marie loved to serve this cake for dessert.
Ingredients You'll Need
2 cups sugar
2 cups flour
1 stick margarine
5 Tbsp. cocoa
1/2 cup shortening
1 cup water
2 eggs
1/2 cup buttermilk
1 tsp. soda
1 tsp. vanilla
Frosting Ingredients
1 stick margerine
5 Tbsp. cocoa
1/2 cup milk
1 cup black walnuts
Directions
Mix sugar and flour in large bowl. In a large sauce pan add margarine, cocoa, shortening, and water. Bring to a boil. Add eggs, buttermilk, soda, and vanilla to a bowl and mix. Combine all three mixtures, pour into greased sheet cake pan. Bake at 400 degrees for 12 minutes. Make frosting and frost cake while hot.
Frosting: Mix margarine, cocoa, and milk in sauce pan. Bring to boil. Remove from burner and add 1 box powdered sugar (1 lb), vanilla and nuts. Ice cake while hot from oven.