Use this royal icing for frosting sugar cookies, including our Citrus Sugar Cookies.
- 4 cups confectioners' sugar, sifted
- 5 tablespoons pasteurized egg whites
- 1/2 teaspoon cream of tartar
Using an electric mixer on low, combine confectioners' sugar, sifted, egg whites, and cream of tartar; beat on high until icing is whipped and opaque, about 2 minutes. Thin with water as needed to make a stiff but spreadable icing.