Snowy Seven-Minute Frosting

In a small, heavy saucepan, combine 3/4 cup sugar, 1/3 cup water, and corn syrup; cook over medium heat, stirring occasionally, until sugar dissolves. Increase heat to high and bring to a boil, washing down sides of pan with a pastry brush dipped in water (to stop crystals from forming). Cook, without stirring, until a candy thermometer registers 230°, about 5 minutes.

Meanwhile, in a mixer fitted with the whisk attachment, beat egg whites on medium speed until soft peaks form, about 2 1/2 minutes. Gradually add remaining 1 tablespoon sugar until combined.

Once sugar syrup has reached 230°, immediately remove from heat. With mixer on medium-low, carefully pour syrup into egg-white mixture, in a steady stream down sides of the bowl (to prevent splattering). Increase speed to medium-high and beat until mixture is completely cool and stiff peaks form, about 7 minutes. Add vanilla and beat until fully incorporated and frosting is shiny and smooth. Use immediately.