Confectioners' Sugar - Mishpacha Magazine
You’ve used the snow white, fine substance in the baking aisle of your supermarket. Confectioners’ sugar is simply granulated sugar that’s been ground and combined with 2–5 percent of some sort of anti-caking agent like cornstarch or potato starch. It’s generally used to make icing or frosting or as a delicate finish to the top
Source: mishpacha.com