Mock Twinkie? Filling

1 cup milk
1 cup granulated sugar
1/2 cup Crisco? (white)
1 teaspoon vanilla extract
5 tablespoons flour
1/2 teaspoon salt
1/2 cup butter

Mix flour with milk; boil until thick, then cool. After mixture has cooled, beat until fluffy (10 to 15 minutes). Add remaining ingredients, beating well as you add them individually, one at a time. Spread the filling between layers of cake.

NOTE: The longer the milk and flour mixture is beaten, the fluffier the filling will be.