Ideal for decorating cookies, royal icing dries quickly and can be tinted with food coloring. You can use the icing to attach decorative candies, colored sugars and small ornaments to the cookies. It's a good idea to flavor the icing with a few drops of vanilla extract or fresh lemon juice.
3 egg whites, at room temperature
4 1/2 cups confectioners' sugar
1/2 tsp. cream of tartar
Pinch of salt
A few drops of vanilla extract or fresh lemon juice (optional)
In the bowl of an electric mixer fitted with the whisk attachment, beat the egg whites, confectioners' sugar, cream of tartar and salt on medium-low speed until blended. Add the vanilla or lemon juice, increase the speed to medium-high, and continue beating until stiff peaks form and the mixture is nearly triple in volume, 7 to 8 minutes.
Remove the bowl from the mixer, cover tightly with plastic wrap and store at room temperature until ready to use, up to 6 hours.