Instructions

1. Place egg whites, sugar and salt in medium-sized heatproof mixing bowl over a pan of simmering water and whisk gently and constantly until egg whites are hot (about 140 degrees) and sugar is dissolved, about 3-4 minutes.
2. Remove from heat and whip by machine until thick and cooled, about 5 minutes. Beat in butter and continue beating until buttercream is smooth and spreadable.
3. Use immediately or refrigerate, covered, for up to 5 days.
4. Before using, bring buttercream to room temperature and beat smooth by machine.
5. Beat in flavoring, a little at a time, and continue beating until buttercream is smooth, about 2 minutes longer (always flavor buttercream immediately before using it.)
6. Flavorings:
7. Liqueur: 2-3 Tbsp. liqueur, such as Grand Marnier or dark or light rum.
8. Lemon: 2-3 Tbsp. lemon juice.
9. Coffee: 3 Tbsp. instant coffee (espresso, if possible) dissolved in 2 Tbsp. water, coffee or rum.
10. Raspberry: 3/4 cup thick raspberry puree made by cooking down and straining a 10-ounce package of frozen raspberries.
11. Chocolate: 6 ounces chocolate melted with 4 Tbsp. water, coffee or milk and cooled.