In the first place, the eggs should be cold, and the platter on which
they are to be beaten also cold. Allow, for the white of one egg, one
small teacupful of powdered sugar. Break the eggs and throw a small
handful of the sugar on them as soon as you begin beating; keep adding
it at intervals until it is all used up. The eggs must not be beaten
until the sugar has been added in this way, which gives a smooth,
tender frosting, and one that will dry much sooner than the old way.
Spread with a broad knife evenly over the cake, and if it seems too
thin, beat in a little more sugar. Cover the cake with two coats, the
second after the first has become dry, or nearly so. If the icing gets
too dry or stiff before the last coat is needed, it can be thinned
sufficiently with a little water, enough to make it work smoothly.
A little lemon juice, or half a teaspoonful of tartaric acid, added to
the frosting while being beaten, makes it white and more frothy.
The flavors mostly used are lemon, vanilla, almond, rose, chocolate
and orange. If you wish to ornament with figures or flowers, make up
rather more icing, keep about one-third out until that on the cake is
dried; then, with a clean glass syringe, apply it in such forms as
you desire and dry as before; what you keep out to ornament with may
be tinted pink with cochineal, blue with indigo, yellow with saffron
or the grated rind of an orange strained through a cloth, green with
spinach juice and brown with chocolate, purple with cochineal and
indigo. Strawberry, or currant and cranberry juices color a delicate
pink.
Set the cake in a cool oven with the door open to dry, or in a draught
in an open window.