Texas Sheet Cake

Cake Batter:
2 c. flour
2 c. sugar
2 eggs
1/2 c. sour cream, buttermilk, or plain yogurt
1/2 tsp. salt
1 tsp. baking soda
2 sticks butter
1 c. water
4 T. cocoa

Frosting;
1 stick butter
6 T. milk
4 T. cocoa
4 c. powdered sugar
1 tsp. vanilla

Mix all the cake batter ingredients except for butter, water, and cocoa. In a saucepan bring the butter, water, and cocoa to a boil. Remove from heat and add to the other ingredients. Combine well and pour into a greased 10x15 sheet pan. Bake for 20 minutes at 350 degrees. While these are baking bring butter, milk, and cocoa for the frosting to a boil in a saucepan. Remove from heat and add powdered sugar and vanilla. Beat until smooth and spread over cooled cake.