1 c. sugar
2 tbsp. (heaping) cornstarch
2 tbsp. (rounded) cocoa
1/2 c. cold water
1 c. hot water
1 tbsp. butter
1 tsp. vanilla

Mix together sugar, cornstarch and cocoa in pan. Add cold water and mix well. Add hot water and cook until thick, stirring constantly. Remove from heat and add butter and vanilla. Cool and frost cake.