Whipped Cream Frosting
["4 Tbsp. flour", "1 c. milk", "3/4 c. butter, softened", "3/4 c. white shortening", "1 c. sugar", "1 1/2 tsp. vanilla or 1 tsp. other flavor extract"]
["In small saucepan, mix milk gradually into flour with wire whisk.", "Cook over medium heat, whisking constantly, until mixture thickened.", "Remove from heat; cover with plastic wrap and set aside to cool."]
["flour", "milk", "butter", "white shortening", "sugar", "vanilla"]