-
Preheat the oven to 350°F. Line two cupcake or muffin pans with papers, and spray the papers with non-stick vegetable oil spray, if desired.
-
Prepare the cake batter from our Favorite Fudge Birthday Cake recipe.
-
Divide the batter evenly among the cupcake cups; you'll pour a scant 1/4 cup batter (about 58g) into each cup. A muffin scoop works well here.
-
Bake the cupcakes for about 25 minutes, until a cake tester or toothpick inserted into the center of one of the cakes in the middle of the pan comes out clean.
-
Remove the cupcakes from the oven. In about 5 minutes, or as soon as you can handle them, remove them from the pan, and place them on a rack to cool.
-
When the cupcakes are cool, make the frosting. Place the 2 egg whites in a large mixing bowl or the bowl of your stand mixer. Beat until the egg whites are foamy and thick; they should mound in the bowl, without holding a peak. Set them aside while you prepare the sugar syrup.
-
Combine the sugar, cream of tartar, water, and salt in a saucepan. Bring to a boil, stirring frequently; the sugar should be dissolved. If the sugar hasn't dissolved, cook and stir a bit more, until it has. Once the sugar has dissolved, boil the syrup, undisturbed, for 2 minutes, or until the syrup registers 240°F on a candy thermometer or instant-read thermometer.
-
Begin to beat the egg whites, and immediately pour the boiling sugar syrup into the egg whites in a slow stream, beating all the while. As you beat, the mixture will thicken.
-
Once all the syrup is added, stir in the vanilla, and continue to beat until the frosting is thick and will hold a peak.
-
Spoon the hot frosting atop the cooled cupcakes, swirling it decoratively.
-
Decorate while warm with sprinkles, mini chocolate chips, sparkling sugar, or the decorations of your choice.
