First, gather up and measure out all the meringue frosting ingredients. Then, fill a saucepan with a couple of inches of water and bring it to a boil.
While the water is heating up, carefully separate the egg whites from the yolks into a mixing bowl.
Next, when the water is boiling, find a heat-safe bowl that will fit on top of the pan without touching the water. In it, mix the egg whites, sugar, and vanilla extract.
Continue to constantly whisk the mixture for about 5- 7 minutes or until a candy thermometer measures the meringue mixture temp at 140°F.
Next, carefully remove the hot mixing bowl from the saucepan and pour the meringue mixture into a large glass mixing bowl.
Then, use a KitchenAid mixer, or stand mixer, with a whisk attachment to beat the meringue until stiff peaks form about five minutes.
If the meringue frosting starts to flatten then just take a whisk and whip it by hand for 2- 3 minutes. Spoon the frosting onto the cooled cupcakes and use a cake spatula to create peaks and edges.To get that lovely toasted marshmallow effect, you can carefully use a kitchen torch to toast and brown the peaks and edges.