Ingredients

Makes 4 cups – Enough to frost the outside of a cake or 12 cupcakes, double if using for filling as well.

5 large egg whites
1 1/4 cups sugar
2 cups (4 sticks) unsalted butter, room temperature
1 teaspoon vanilla extract
1/4 teaspoon coarse salt

Directions

1. Combine egg whites, and sugar in the heat proof bowl of an electric mixer. Set bowl over a pan of simmering water. Stir constantly with a wooden spoon until sugar has dissolved and whites are 140 degrees use a candy or instant read thermometer), 5 to 7 minutes.
2. Transfer bowl to the electric mixer. Using the whisk attachment, mix on low speed, gradually increasing to high speed, until stiff, glossy peaks form, about 10 minutes.
3. At low speed, add butter to egg whites, and beat until smooth. Add vanilla and salt, and continue mixing until incorporated.

Can be flavored with 8 oz cooled melted chocolate or thick fruit puree, add slowly and monitor consistency to prevent over-thinning