Batch for 6-inch double layer cake:
6 egg whites
1 cup/200g sugar
Pinch of salt
1 pound unsalted butter, cubed, softened (room temperature works too, but takes longer to come together)
3 teaspoons clear vanilla extract
Large batch (make once for 3-4 large tiers, or make 2-3 times for many-tiered cakes):
12 egg whites
2 1/2 cups/500g sugar
1/4 tsp salt
5 cups unsalted butter, softened
1 tbsp clear vanilla extract
- Set a saucepan filled one-third full of water over medium-high heat and bring to a simmer.
- Whisk together the egg whites, sugar, and salt in a large heatproof bowl ( I suggest a stainless bowl). Set over the simmering water and whisk until the mixture is hot to the touch and the sugar has dissolved (120-140 degrees on a candy thermometer, to be sure).
- Transfer the mixture to the bowl of a stand mixer fitted with the whisk attachment.
- Beat on low speed for 2 minutes. Increase to medium-high until stiff peaks are formed.
- Continue beating at medium-high speed until the mixture is fluffy and has cooled (the mixing bowl should feel cool to the touch).
- Turn the mixer off and switch from the whisk attachment to the paddle. Turn the mixer on medium-low and add the butter, a few cubes at a time, beating until well incorporated before the next addition.
- Add the vanilla extract. Divide batter and tint with food coloring, if desired.
- Beat until the frosting is thick and completely smooth.
- Store in an airtight container until ready for use.