Royal icing is a smooth, hard-drying icing used in holiday baking recipes as well as wedding cakes. Try using royal icing to decorate the tops of your favorite Valentine's, Easter or Christmas cookies; to create delicate flower cake decorations; or to act as cement for gingerbread houses. Royal icing can be made using egg whites, cream of tartar or meringue powder.
Combine 4 cups of confectioner's sugar (powdered sugar), 6 tablespoons of warm water and 3 tablespoons of meringue powder in a large bowl. You can find this in the cake supplies aisle at craft stores.
Mix the ingredients together for about 15 to 30 seconds using a low setting. Increase the speed, and beat until the icing forms peaks, from 7 to 12 minutes depending on your mixer.
Cover any portions not in use to prevent hardening.
Use tints to achieve any color you wish. Otherwise, royal icing will be true white with a sheen when dry. Color is available in gel or powder forms.