1 stick butter
8 tbsp. Crisco shortening
1 c. confectioners' sugar
3 tbsp. regular flour
2/3 c. milk, must be room temp.
1/2 tsp. vanilla extract (opt.)

Cream butter, shortening, confectioners' sugar and flour. Add milk (and vanilla if desired), a little at a time. Beat well, around 15 minutes. Icing should be kept refrigerated.