Combine ½ c butter, 4 Tbsp cocoa, shortning, and water. Bring to a rapid boil. Pour this hot mixture over the sifted flour and sugar. Mix well. Add buttermilk, eggs, baking soda and 1 tsp vanilla. Pour into a greased and floured 15 x 10 inch pan. Bake @ 400 for 18 minutes. While cake bakes, combine ½ c butter, milk and 4 Tbsp cocoa in a saucepan. Bring to a boil. Remove from heat. Add powdered sugar and 1 tsp vanilla. Beat well. Frost cake while it's still warm.
Recipe originally received from Betty Kalmes.