This sweet, fluffy icing, known as a seven-minute frosting, has been a favorite among bakers since the 1930s. Its texture is similar to meringue.
4 egg whites
1 1/3 cups sugar
1/2 cup light corn syrup
1/4 tsp. salt
1 tsp vanilla extract
1 cup sweetened shredded coconut
In the bowl of an electric mixer, using a handheld whisk, beat together the egg whites, sugar, corn syrup and salt just until combined, about 30 seconds. Place the bowl over but not touching simmering water in a saucepan and whisk until the sugar dissolves and the mixture is hot, 2 to 3 minutes.
Set the bowl on the mixer fitted with the whisk attachment and beat on medium speed for 3 minutes. Add the vanilla and beat until the outside of the bowl is cool and stiff peaks form 5 to 7 minutes more. Using a rubber spatula, fold in the coconut just until incorporated.