Often called Seven-Minute Frosting because of the usual beating time, this venerable favorite is the classic finish for many cakes. For a less-sweet version, reduce the amount of sugar to 3/4 cup, or substitute 1/3 cup light corn syrup for the water and sugar.
Pour water into a large skillet to a depth of 1 inch. Place over high heat and bring to a simmer, then adjust the heat to maintain a simmer.
In a metal bowl, combine 5 Tbsp cold water, the sugar, egg whites, corn syrup, cream of tartar, and salt. Set the bowl directly into the simmering water. Immediately begin to beat with a hand mixer at low speed until the mixture is foamy, then increase the speed to high and continue beating until firm, shiny peaks form, about 5 minutes.
Remove the bowl from the heat, add the vanilla, and continue beating until the frosting is cool and billowy, 2 to 3 minutes.
Use immediately, or cover and refrigerate for up to several hours; some of the volume will be lost during storage.
- Fluffy Brown Sugar Frosting – Substitute firmly packed brown sugar for the granulated sugar.
- Fluffy Citrus Frosting – Substitute 5 Tbsp freshly squeezed orange or tangerine juice for the water, or 3 Tbsp freshly squeezed lemon or lime juice for 3 Tbsp of the water. Add 1 tsp finely grated or minced fresh orange or tangerine zest or 1/2 tsp lemon or lime zest along with the other ingredients before heating.
- Fluffy Coconut Frosting – Stir about 3/4 cup grated or shredded fresh coconut or packaged sweetened coconut into the finished frosting.
- Fluffy Coffee Frosting – Combine 1 Tbsp instant espresso, or to taste, with just enough hot water (1 to 2 tsp) to dissolve the espresso and add along with the vanilla.
- Fluffy Nut Frosting – Toast 1 cup nuts, then chop finely and stir into the finished frosting.
- Fluffy Peppermint Frosting – Substitute 1 tsp pure peppermint extract, or to taste, for the vanilla.