This recipe is the best decorator's icing, I've every made. I found this recipe in a "Martha Stewart Living Magazine" many many years ago and I still use it to this day. It does great on Christmas cookies.
2 large egg whites
4 c. sifted confectioners sugar
juice of 1 lemon and 3 drops of glycerin (optional)
Beat egg whites until stiff but not dry. Add sugar; beat for 1 minute more.
If icing is too thick, add more egg whites; if too thin, add more sugar.
Makes about 2 cups