This can be flavored and colored as desired, for example, by using lemon juice in place of the water. More complicated icings can be made by beating fat into powdered sugar (as in buttercream), by melting fat and sugar together, by using egg whites (as in royal icing), and by adding other ingredients such as glycerin (as in fondant). Some icings can be made from combinations of sugar and cream cheese or sour cream, or by using ground almonds (as in marzipan).