in sauce pan bring to boil 1 C margarine 3T cocoa and 1 C water. Mix in flour mixture add 3 eggs 1 tsp baking soda, 1/2 C buttermilk 1 tsp vanilla and 1 tsp cinnaman. Bake at 350 degrees for 20 minutes in greased & floured Sheet cake pan.
Frosting. 1/2 C. mrgarine 3 T cocoa, 6T Buttermilk. simmer remove from heat...Beat in 3/4 to 1 bpx powdered sugar. Add 1 tsp vanilla. Pour over Hot cake.