1/2 c. softened butter
3/4 c. sugar
2/3 c. milk
4 tsp. flour
3/4 tsp. vanilla

In small mixer bowl, cream butter and sugar. In small saucepan combine milk and flour. Cook, stirring over low heat until it comes to a boil and is thickened. Cool. Add cooled past mix and vanilla to butter mixture, blend well. Spread on cake.