(recipe from blogger sweet fiend).
3 large egg whites, at room temperature
a Pinch salt
1 cup unsalted butter, room temperature and cut into 16 pieces
1. Combine egg whites and sugar in a large heat proof bowl. Set the bowl over (not on) simmering water in a sauce pan and heat, whisking constantly until sugar has dissolved. The mixture is ready when with it is very warm to the touch, about 2 minutes and approximately 160 degrees on an instant read thermometer.
2. Remove from mixture from heat and transfer to a stand mixer bowl and beat on high until egg white mixture is fluffy, led to room temperature and holds stiff peaks, about 6 minutes.
3. Turn the speed to medium low, add salt and the butter a few pieces at a time, beating well after each addition. Turn the speed to high and beat until mixture is creamy, about 3-5 minutes more. Add flavorings as you like such as 4 ounces of melted dark chocolate or two tablespoons of your favorite liquor and/or a little cocoa powder.