Confectioners sugar is a type of sugar that has been finely ground into a powdery form. It is also known as powdered sugar or icing sugar. The sugar is pulverized to a powder so fine that it's basically sugar dust. Cornstarch is added to prevent the powder from clumping, but it won't affect the taste. Confectioners' sugar dissolves very easily, so it's the preferred sugar for baked good decorations such as frosting, icing, and dusting. It is also used in candy and fudge recipes as well as dense cookie and dessert bar recipes. Confectioners' sugar behaves differently than other forms of sugar in recipes, and there's generally a reason it's used instead of granulated sugar. For instance, icings, frostings, and candies use confectioners' sugar because it dissolves easily and provides a smooth consistency. It is also used in meringue recipes, where it acts as a stabilizer.
Confectioners' sugar is not the same as granulated sugar. Confectioners' sugar is granulated white sugar that has been pulverized to a fine powder, while granulated sugar is sandy and coarse. Most powdered sugar in the US comes in 3X grind, while confectioner's sugar is powdered sugar with cornstarch added to prevent caking of the sugar. If you don't have confectioners' sugar on hand, you can make it at home by grinding regular sugar in a food processor or blender until it reaches the desired consistency.
