Preheat oven to 375 degrees
Spray a 13 x 9 pan with non-stick cooking spray and shake flour onto pan coating all sides
Combine flour, sugar, cinnamon, baking soda and salt and stir
Combine water, butter and cocoa in a saucepan and bring to boil, remove from heat and pour into flour mixture
Beat with mixer until blended and then add vanilla, buttermilk and eggs and beat until smooth
Pour batter into pan and bake for 20 - 25 minutes
Allow cake to cool before frosting the cake with the following: