1 c. milk
2 tbsp. cornstarch
1/2 c. butter
1/2 c. vegetable shortening
1 c. confectioners sugar
1 tsp. vanilla

Blend milk and cornstarch in small saucepan. Cook and stir over low heat until thickened. Chill thoroughly. Cream butter, shortening, and sugar. Beat in chilled paste and vanilla. Beat at high speed until mixture resembles whipped cream. Mixture will frost and fill a 9 inch layer cake.