Spread blue frosting in upper left corner. Pipe stars in blue field with reserved 1/4 cup vanilla frosting. Shortly before serving, place strawberries in seven rows to represent red stripes of flag. About 15 servings. * To sour milk: Use 2 teaspoons white vinegar plus milk to equal 2/3 cup. Hershey's is a registered trademark of Hershey Foods Corporation. Recipe may be reprinted courtesy of the Hershey Kitchens.