In a medium saucepan, combine the granulated sugar and water. Place it over medium heat and stir until the sugar dissolves completely. Bring the mixture to a gentle boil, and let it cook without stirring until it reaches a soft-ball stage, about 5-7 minutes.
While the sugar syrup is cooking, place the egg whites, cream of tartar, and a pinch of salt in a mixing bowl. Beat the egg whites on medium speed until frothy, then increase to high speed until soft peaks form.
Once the sugar syrup has reached the correct temperature, remove it from the heat. With the mixer running on medium speed, carefully pour the hot syrup in a thin stream into the whipped egg whites. Continue to beat until thick and glossy, about 5-7 minutes.
After the frosting has thickened, add the vanilla extract and mix until just combined. Your 7 Minute Frosting is now ready to be used!