For an especially glossy icing, mix in a few drops of glycerin (available at drugstores).
- 2 large egg whites, or more to thin icing
- 4 cups sifted confectioners' sugar, or more to thicken icing
- Juice of 1 lemon
- 3 drops glycerin
Beat the whites until stiff but not dry. Add sugar, lemon juice and glycerin (if using); beat for 1 minute more. If icing is too thick, add more egg whites; if it is too thin, add more sugar. The icing may be stored in an airtight container in the refrigerator for up to 3 days.