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. It won't look like Icing at first, but keep the mixer going for a full five minutes, and then you're done!

Note: If you're not using this for decorating, but just for icing the cake, thin the icing by adding 3 tbs. of corn syrup, or water to the icing.