Perfect Seven-Minute Frosting

1. In a small, heavy-bottom saucepan, combine 3/4 cup sugar, corn syrup, and 4 tablespoons water. Place over medium heat, stirring occasionally, until sugar has dissolved, about 4 minutes. Rub a bit of the mixture between your fingers, making sure any graininess has disappeared. Raise heat, and bring to a boil without stirring. Continue boiling, occasionally washing down the sides of the pan with a pastry brush dipped in cold water to prevent sugar from crystallizing, until a candy thermometer registers 230 degrees, about 5 minutes. (Depending on the humidity, this can take anywhere from 4 to 10 minutes.) Remove the syrup from heat (temperature will keep rising).

2. Meanwhile, in the bowl of an electric mixer, whisk the egg whites on medium speed until soft peaks form, about 2 1/2 minutes. Gradually add remaining 2 tablespoons sugar. With mixer on medium-low speed, pour syrup in a steady stream down side of bowl (to avoid splattering).

3. Beat the frosting on high speed until cool, about seven minutes. It should be thick and shiny. Use immediately.

Cook's Notes

Have the cake you are going to frost already prepared before making the frosting; it must be spread on while the beaten egg whites and sugar are still pliable; once frosted, the cake may sit out for several hours before being served.