Swiss meringue buttercream, produced with whipped egg whites,
is airier and more stable than American buttercream , yet its texture is unmatched.
Smoothly spread this silky frosting on layer cakes, sheet cakes, and cupcakes.
Whisk egg whites and sugar over a double boiler till 140° to produce Swiss meringue buttercream.
Rub egg whites between your fingers—ready ones shouldn't have sugar grains.
After frothing the egg whites in a stand mixer, add the butter and flavorings.
Chill the bowl for 15 minutes, then whip.