Patty'S Cooked Frosting
["3/4 c. milk", "3 Tbsp. flour", "1 tsp. vanilla", "1/2 c. margarine, softened", "1/2 c. shortening (butter flavor is best)", "1 c. sugar"]
["Combine milk, flour and vanilla in a saucepan over medium heat, whisking constantly, until thick.", "This mixture must completely cool!", "Add remaining ingredients.", "Whip until sugar dissolves and frosting is fluffy.", "Spread on your favorite cake."]
["milk", "flour", "vanilla", "margarine", "shortening", "sugar"]