Royal icing is the frosting that top bakers and cake decorators use to make the perfect details on their cakes and cookies. This icing can be used for many things in cake decorating, but the most popular use is for decorating cookies.
In large bowl of stand mixer with a paddle attachment, combine the egg whites (and vanilla) and beat until frothy.
Add powdered sugar gradually and mix on low speed until sugar is incorporated and the mixture is shiny.
Turn speed up to high and beat until mixture forms stiff, glossy peaks. This step should take approximately 5 to 7 minutes.
Add vanilla and food coloring, if desired. For immediate use, transfer icing to a pastry (piping) bag or heavy duty storage bag and pipe as desired.