• 6 large egg whites (7 ounces)
• 2 cups granulated sugar
• 2 cups (4 sticks) unsalted butter, room temperature
• 1 teaspoon vanilla extract
• 1/4 teaspoon salt

1. Place egg whites and sugar in an electric mixer bowl and place the bowl over a pot of simmering water. (Keep the bowl from touching the water.) Whisk the egg whites over the simmering water until sugar is completely dissolved and egg whites reach a temperature of 120℉.
2. Remove the bowl from the simmering water and place in a stand mixer fitted with a whisk attachment. Whisk on medium-high speed until stiff, glossy peaks form and bowl is room temperature (about 10 to 15 minutes).
3. Remove whisk attachment and replace it with a paddle attachment. Add butter 1 tablespoon at a time, waiting until each addition is incorporated before adding the next. Scrape the bottom of the bowl and increase the speed to medium-high for 3 to 4 minutes, until the mixture is thick and smooth. Add vanilla extract and salt and mix on high for 30 to 60 seconds.

NOTES

• It is very important that the sugar is completely dissolved before it’s taken off the stove. If not, the buttercream will be grainy. Before removing it from the simmering water, rub a little between your finger and thumb; there should be no granules.
• For best results, make sure butter is at room temperature.
• Wait for the mixture to cool completely before adding butter. If mixture is even slightly warm, it will melt the butter.
• If the frosting is too thin, place the bowl in the refrigerator for 5 to 10 minutes and then continue to mix on high for 30 to 60 seconds.