Chocolate Sheet Cake
["2 c. flour", "2 c. sugar", "1 stick margarine", "1/2 c. shortening", "4 Tbsp. cocoa", "1 c. water", "1/2 c. buttermilk", "2 eggs, slightly beaten", "1 tsp. soda", "1 tsp. vanilla"]
["Mix in saucepan, margarine, shortening, cocoa and water and bring to boil.", "Pour over flour and sugar.", "Add other ingredients. Bake in shallow greased pan (20 x 13-inch) at 375\u00b0 for 20 minutes or until it springs back to touch.", "Five minutes before cake is done, prepare frosting."]
["flour", "sugar", "margarine", "shortening", "cocoa", "water", "buttermilk", "eggs", "soda", "vanilla"]