Crystallization consists in simply covering the cake while the icing is wet with granulated sugar, plain or pink. (For coloring sugar pink see "meringue icing"). Or you can use pink or white sugar or rock candy crushed. If you wish to crystallize only a portion of the icing, and that in any particular design, first allow the icing to dry, then wash the part you wish crystallized with white of egg or gum-water, and cover it with the sugar; then shake off what will not remain on.
Take any quantity of powdered sugar you require, add cold water enough to it to form a thick paste (remember, it will not take much); beat well, and if too thin so that it runs too much, add a little more sugar. To every pound of sugar, add as much cream of tartar as will lie on a twenty-five cent piece (a level teaspoon-ful); when this icing is prepared, spread it with a knife over the cake, and allow it to dry; you can then ornament or decorate it with icing sugar in the same manner as for a bride's cake, or use a sweet jelly, such as "red currant" or "quince."
This water icing may also be colored a light shade of pink with "cochineal," or a light cream color with saffron. For a mauve color, add a drop of indigo blue to the pink color; but remember none of these colors must be heavy, as they are objectionable and in bad taste. Water icing is used for tops of pound, sponge, and other cakes, also for tops of jelly cakes. (See design for jelly cake, page 353.)
What is known as cream chocolate icing is done in the same manner, using half cocoa and half pure cream, and sweetening it to taste. In this case use no whites of eggs, but simply dissolve the cocoa as before described, then add the sugar, and afterwards gradually add and well stir in the cream. It is then ready for use. Chocolate icing is also used to ice jelly cakes and other small cakes, also chocolate-de-clares; it may also be used as an icing for any thing, and can be piped, ornamented, or decorated with icing sugar in the same manner as a bride's cake.
Cocoa may also be mixed with sugar icing; add little or much cocoa as desired, and either ice a cake with this chocolate icing or use it for piping or ornamenting in the same manner as icing sugar is used.