I love using this for my mini s’mores cake recipe, but it would probably be magical on lots of different types of cake. Or you can skip toasting it and just use it as a desserty dip!
One rule before we begin: No fat allowed. This means you can’t let even a speck of egg yolk into your egg whites, and you must start with a clean and grease-free bowl. (Which is why you often hear “don’t use a plastic bowl” when it comes to stuff like this—plastic likes to hold onto fats and oils.)
Toasted Marshmallow Frosting
Makes enough for 12 cupcakes or for half of a standard double-layer 9″ round cake.
4 egg whites
1 cup sugar
1/4 tsp cream of tartar
a dash of salt
a splash of vanilla
Combine the egg whites, sugar, cream of tartar, and salt in a heat-proof bowl. Set the bowl over a pot of low, simmering water.
Whisk these ingredients constantly for about 4 minutes over the simmering water. The sugar should melt completely, and your mixture should look frothy.
Remove the bowl from heat and beat your mixture for 5 to 7 minutes, gradually increasing from low to high speed.
Finish by whisking in the vanilla.
Note: Don’t refrigerate the batter! That will kill your fluffy egg whites.
And to toast it…
You’ll need your broiler! Go ahead and turn it on.
Once the broiler is ready, set your frosted cupcakes or cake or whatever-it-is on a cookie sheet.
Slide the cookie sheet under the broiler (not too close), and let it toast your frosting for about 30 seconds. That’s it!
…or you can just use a kitchen torch. But I’m all about having as few kitchen utensils as possible.