- 120 g (4 large) egg whites
- 330 g (1 1/2 cups) granulated sugar
- 452 g (1 pound) unsalted butter, softened
- 6.3 g (1 1/2 teaspoons) pure vanilla extract
- Put the sugar and egg whites in a mixer bowl and whisk together. Make a double boiler by placing the bowl over a saucepan of simmering water (ensuring the bowl does not touch the water). Whisk constantly until the sugar is completely dissolved and the mixture feels hot to the touch, about 4-5 minutes. You should not feel any sugar granules when rubbing the mixture between your fingertips.
- Transfer the bowl to the stand mixer fitted with the whisk attachment. Whip the mixture on medium-high until the bottom of the bowl no longer feels warm and the meringue is thick and glossy.
- With the mixer on medium, add the softened butter half a stick at time. Continue to whip until mixture is smooth. Mix in vanilla until completely incorporated.