Royal Icing is made with egg-whites, lemon and icing sugar. It sets hard and is ideal for frosting biscuits.
Royal Frosting can also be used to make decorations such as flowers and figures for decorating cakes and biscuits. The icing can be piped into shapes which are left to set on a non-stick surface.
You will often see picture of Christmas cakes, wedding cakes, biscuits and gingerbread houses which have been frosted with royal icing. When used for biscuits and gingerbread houses it is usually applied smoothly, whereas for cakes it is often left in sharp peaks.
The easy royal icing recipe that I use does not contain glycerine. Glycerine is often included as it stops the icing from setting too hard. This is useful if you are wanting to apply the icing to cakes and want them to have peaks.
Cupcake Frosting Recipes