Ingredients

10 large egg whites 

2 1/4 cups sugar 

1/4 teaspoon salt 

4 cups (8 sticks) unsalted butter, softened 

1/2 cup cream of coconut 

1/2 teaspoon pure coconut extract 

Preparation

Whisk egg whites, sugar, and salt in the heatproof bowl of an electric mixer set over a pan of simmering water until sugar has dissolved and mixture registers 160 degrees, about 3 minutes.

Attach bowl to mixer fitted with the whisk attachment. Beat on medium-high speed until cooled, about 10 minutes. Reduce speed to medium. Add butter; beat until pale and fluffy. Mix in cream of coconut and extract.