1. In saucepan, bring butter, shortening, water and cocoa to a boil.
2. Take off heat and add sugar, flour, eggs, buttermilk, baking soda, vanilla and cinnamon.
3. Heat well stirring constantly.
4. Pour in a greased 9x13-inch pan. Bake at 400°F for 20-25 minutes.
5. ICING DIRECTIONS:.
6. Blend together all ingredients until well mixed.
7. While cake is hot, poke holes throughout the cake. Spread Icing onto HOT cake.