7 Minute Frosting is light and fluffy and has the perfect bright white color. This meringue-like frosting will practically melt in your mouth and it takes less than 10 minutes to make.
Select a heat-safe metal or glass mixing bowl that can sit on top of a saucepan without touching the water below to create a double boiler. Pour 2 inches of water into the saucepan. Bring the water to a boil, then reduce the heat to medium or medium-low to maintain a simmer.
While the water is heating, place the egg whites, sugar, water, salt, and cream of tartar into the heat-safe mixing bowl.
Set the bowl over the simmering water. Using a hand mixer, or whisking vigorously by hand, beat the egg mixture for about 7 minutes until it becomes thick and glossy. Place the bowl over the simmering water. Using a hand mixer, or whisking vigorously by hand, beat on medium speed for 7 minutes. The mixture should become thick, glossy, and increase in volume. At 3 minutes, increase the mixer speed as the mixture becomes creamier.
Carefully remove the bowl from the saucepan and place it on the counter. Add the vanilla extract and continue to beat with the hand mixer for an additional 1 to 2 minutes, until stiff peaks form. The frosting should hold its shape when lifted.