Place 2 sticks margarine, 4 tablespoons cocoa and 1 cup water in a saucepan and bring to a boil.
Set off immediately and add 1/2 cup buttermilk and 1 teaspoon soda. (I measure the buttermilk and stir the soda into it and then add it to the chocolate mixture.)
Add 2 cups flour and 2 cups sugar and mix until smooth.
Add 2 beaten eggs and 1 1/2 teaspoons of vanilla.
Beat with a mixer until batter is smooth.
Pour into a greased and floured cookie sheet.
Sometimes I sprinkle chopped pecans on top and do not frost the cake.
Bake at 400 degrees for 25 minutes.
If you wish you can ice with with your favorite frosting or use the following:
Combine 2 cups powdered sugar, 3 or 4 tablespoons cocoa and 1/3 cup Crisco, 1 egg and 1 tablespoon vanilla and a dash of salt. Beat like thunder.