Up the tropical flavors in the Dreamy Coconut Wedding Cake with this coconut version of the classic Swiss Meringue Buttercream.
Put sugar and egg whites in the heatproof bowl of an electric mixer, and set over a pan of simmering water. Whisk constantly until sugar is dissolved, and mixture registers 140 degrees on an instant-read thermometer.
Transfer bowl to an electric mixer fitted with the whisk attachment. Beat on medium-high speed until fluffy and cooled, about 10 minutes. Continue beating until stiff, glossy peaks form.
Reduce speed to medium-low; add butter by the tablespoon, beating well after each addition. Beat in vanilla, and coconut. Buttercream can be refrigerated in an airtight container up to 3 days or frozen up to 1 month. Bring to room temperature before using; beat on lowest speed until smooth, about 3 minutes.