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.
In a large bowl, combine sugar, shortening, water and vanilla. Beat on low speed to combine, then beat on medium speed for a full five minutes.