1 cup milk
1/4 cup flour
1 cup sugar
1 teaspoon vanilla
1/2 cup butter
1/2 cup Crisco

Mix milk and flour together and cook in microwave until thick. Stir once. Cool. In a mixer bowl, beat sugar, vanilla, butter and Crisco until fluffy. Add cooked mixture and beat until well blended and thick. Spread on cooled cake. Does not harden and is not sweet.