Ice Cream Frosting

A boiled-syrup meringue frosting, given in the shorthand Fannie Farmer used once a base method had already been printed. Everything depends on the syrup, so read the White Mountain Cream method first.

• The stray "1 cup sugar"The line at the end does not belong with this recipe; it appears to have drifted in from the adjacent recipe on the page. Use 1½ cups sugar, ½ cup water, 2 egg whites and 1½ teaspoons vanilla.
• The hinge: syrup temperatureBoil the sugar and water without stirring. The recipe itself gives no test, deferring to White Mountain Cream, where the syrup is judged by eye rather than by thermometer; a modern cook working to roughly 238-240F on a candy thermometer will be in the right range. Under-boiled syrup gives a frosting that never sets; boiled much beyond that it turns grainy and tears the cake.
• Adding the syrupBeat the whites to stiff-but-not-dry, then pour the hot syrup in a thin, steady stream down the side of the bowl with the mixer running. Dumping it in cooks the whites into threads.
• Beating timeContinue beating 6-8 minutes, until the mixture holds a peak, looks satiny and the bowl is only just warm. Beat in the vanilla at the very end; heat drives off the flavor.
• Working speedThis frosting crusts as it cools. Spread it on a completely cold cake, all at once, and finish the swirls immediately rather than going back over set patches.
• YieldRoughly enough to cover the top and sides of one 8- or 9-inch two-layer cake.
• Raw-egg noteThe hot syrup heats the whites but does not reliably pasteurize them. Pasteurized egg whites are a straightforward substitute if serving anyone who should avoid raw egg.