Usual proportions are 2 egg whites to 1 teaspoon of lemon juice, 1 teaspoon of glycerine, and around 1 pound of sugar depending on the application. As well as coating cakes and biscuits, royal icing is used to make decorations such as flowers and figures for putting on the cake. The royal icing is piped into shapes which are allowed to harden on a royal icing for sugar cookies-stick surface. These can then be arranged to create edible decorative effects on a variety of sweet foods.
The glycerine must be omitted for this purpose. Royal icing is traditionally prepared with raw egg whites, which have a very small chance of transmitting salmonella poisoning. The Oxford Companion to Sugar and Sweets. They are not very difficult to make when following this recipe and a few easy tips!