Fondant is a sweet mixture made from sugar, water, and cream of tartar and used as an icing and sometimes a candy. The mixture is cooked to the soft ball stage then beaten and kneaded until it is pliable. Fondant makes a smooth icing very popular on wedding and other elegant cakes. The fondant can also be formed into candy and coated in chocolate or dipped in nuts.
You can make your own fondant or it can be purchased in cake decorating supply shops.