How to make Royal Icing. This smooth, hard-drying icing is perfect for making decorations that last. It is also useful as a "cement" to fasten decorations together. Royal icing is edible, but not recommended for icing cakes.
Alton Brown's Royal Icing Recipe: "Fantastic icing! This is my new go-to icing for decorating cookies. I love that it hardens to a clean smooth finish. I can stack cookies easily in a container and not have to worry that the icing is sticking. This is the perfect icing!"