This section is from the book "The Century Cook Book", by Mary Ronald. Also available from Amazon: The Century Cook Book.
Place the white of an egg in a bowl or plate. Add a little lemon-juice or other flavoring, and a few drops of water. Stir in powdered sugar until it is of the right consistency to spread. While the cake is still warm pile the icing on the center of the cake, and with a wet knife smooth it over the top and sides of the cake. It will settle into a smooth and glossy surface. If the icing is prepared before the cake is ready, cover it with a wet cloth, as it quickly hardens. If it becomes too stiff add a, few drops of water, and stir it again. Color and flavor as desired. One egg will take about a cupful of sugar, and will make enough icing to cover one cake. If a little more is needed add a little water to the egg, and it will then take more sugar. "When icing is wanted for decorating a cake, beat the whites to a froth, then beat in the sugar instead of stirring it, and continue to beat until it is firm enough to hold its form. Stirring more sugar into the unwhipped whites will make it firm enough for decorating, but the whipped icing is better. Put it into a pastry-bag with small tube, or into a paper funnel, and press it through into any shapes desired. A good icing is made of milk and sugar alone.
Make this icing the same as the other, using confectioner's sugar, which is finer than the powdered sugar, and use a little water with the egg. This makes a soft, creamy icing; the more water used, the softer it will be. If beaten instead of stirred it will become firm enough to hold in place without so much sugar being used, but in this way it dries sooner and is not so creamy. This is a good icing for layer cakes, fancy cakes, and eclairs.
Put a cupful of sugar into a saucepan with one quarter cupful of boiling water and a half saltspoonful of cream of tartar; stir till dissolved, then let it boil without stirring until it threads when dropped from the spoon. Turn it in a fine stream onto the white of one egg whipped to a stiff froth. Beat the egg until the mixture becomes smooth and stiff enough to spread, but do not let it get too cold. Pour it over the cake.
Boil sugar as directed above to the soft ball; then remove from the fire, add the flavoring, and stir it until it looks clouded, and turn it at once over the cake.'"
Melt in a dry saucepan some chocolate; dilute it with a little water and add enough powdered or confectioner's sugar to make it of the right consistency. Use it while warm, as chocolate quickly hardens. Flavor it with vanilla.
Melt in a dry pan four ounces of chocolate, or of cocoa. Boil one and three quarter cupfuls of sugar with a cupful of water till it threads when dropped from the spoon, the same as for boiled icing. Turn it slowly onto the chocolate, stirring all the time. Use this icing for dipping eclairs and small cakes, and for layer cakes. Chocolate icing loses its gloss when at all stale.
Melt one ounce of chocolate; dilute it with two tablespoonfuls of milk; add two tablespoonfuls of sugar and a quarter teaspoonful of butter; stir till smooth and spread on the cake.
Stir into confectioner's sugar enough syrup of thirty degrees (see page 513) to dissolve it; add fruit-juice or liqueur to flavor it. When ready to use, heat it, stirring all the time, and stand it in a pan of hot water while the cakes are dipped into it.
Make the same as the one given above, using very strong coffee or coffee essence to color and flavor it. Use enough sugar to make a soft flowing icing, and dip the cakes into it while it is hot.
This is the best of all icings. It is soft and glossy, and is used especially for small cakes and eclairs. If the fondant is already made, it gives very little trouble. To make fondant see page 514. It will keep in tight preserve jars any length of time. F does not work so well after it has been melted two or three es, therefore it is better to take only the amount to be used one flavor or color at a time. Place it in a cup and stand it in a pan of boiling water. Stir the fondant constantly while it is melting, or it will become a clear liquid. It will soften at a low degree of heat; add the flavoring and coloring and dip the cakes into it. If it becomes too hard, add a few drops of syrup at thirty-four degrees (see page 513). When liqueurs are used for flavoring, add a drop or two at a time only, or they will dilute it too much. Should this occur, add a little more fondant to the cup. Maraschino, Curacao, kirsch, orange-flower water, rose, almond, and coffee essences make good flavorings for fancy-cake icings.
 
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