Fluffy White Frosting

In a saucepan, stir together the sugar, water and cream of tartar. Cook over medium-high heat until the sugar is dissolved and the mixture is bubbly.
In a medium mixing bowl, whip the egg whites and vanilla to soft peaks. Gradually add the sugar mixture while whipping constantly until stiff peaks form, about 7 to 10 minutes. Frost the cake of your choice.