Meringue Buttercream

Combine egg whites and sugar in a heat-safe bowl. Set the bowl over a pot of simmering water. Whip mixture until the temperature reaches 120 degrees F (49 degrees C) on a digital or instant thermometer and sugar is dissolved about 5 minutes.

Remove egg white mixture from heat. Continue to whip until soft peaks form and the meringue temperature has come down to 99 degrees F (37 degrees C) or lower 4 to 7 minutes.

Add butter to the meringue 2 tablespoons at a time whipping until incorporated and fluffy. Scrape the sides of the bowl and keep mixing until smooth 5 to 8 minutes. Add vanilla extract and whip until incorporated.