Step 1

Fill a medium saucepan with an inch or two of water and bring it to a simmer over medium heat. Whisk together the egg whites, granulated sugar, and cream of tartar in a heatproof bowl, then place it on top of the simmering saucepan. Make sure that the bottom of the bowl does not touch the water. Alternatively, you can use a double boiler for this part.

Step 2

Whisk the egg white mixture continuously until the sugar and cream of tartar are dissolved, about 4 minutes. It will thin out and be very frothy on top.

Step 3

Remove the mixture from the heat and add it to a stand mixer fitted with the whisk attachment (you can use a hand mixer for this part as well). Add the vanilla, then beat on high speed for about 5 minutes. You’ll know it’s ready when it looks glossy with stiff peaks. To test it, dip your whisk attachment into the meringue and make sure the peak holds.

Step 4

Use the Marshmallow Meringue immediately on cakes, cupcakes, or any dessert. You can frost with it, pipe with it, use it as a filling, or whatever you’d like before toasting with a kitchen torch (it tastes great untoasted too though).