Combine flour, sugar, and baking soda. In large saucepan, combine butter, water, cocoa, bring to a boil. Remove from heat. Add flour mixture, eggs, buttermilk, and vanilla. Beat 2 minutes, pour into pan, and bake. Grease 9X13 pan, bake at 375*F for 20-30 minutes. Cream butter until light. Add xxx sugar and vanilla and half and half. Beat until light/spreading consistency. Ice cake.