1 c. sugar
1/2 c. water
1 egg white
Pinch of cream of tartar
Put the sugar and water to cook in a saucepan. Boil until a fairly hard
ball is formed when the sirup is tried in cold water or until it threads
when dropped from a spoon, as shown in Fig. 25. If a thermometer is used
to test the sirup, it should register 240 to 242 degrees Fahrenheit when
the sirup is taken from the stove. Beat the egg white, add the cream of
tartar, and continue beating until the egg white is stiff. Then, as in
Fig. 26, pour the hot sirup over the beaten egg white very slowly, so as
not to cook the egg, beating rapidly until all the sirup has been added.
[Illustration: FIG. 24, Smoothing surface of icing with knife.]
Continue to beat with a spoon or egg whip until the icing is light and
almost stiff enough to spread on the cake, as in Fig. 27. Then place the
bowl over a vessel containing boiling water, as in Fig. 28, and beat for
3 or 4 minutes while the water boils rapidly underneath. With this
treatment, the icing will not change in consistency, but will become
easier to handle and will permit of being used for a longer period of
time without becoming hard. In fact, it may be kept until the next day
if desired by placing a moist cloth over the top of the bowl so as to
prevent a crust from forming.
[Illustration: FIG. 25, Testing hard ball stage of sirup.]