Making your own powdered sugar at home is easy and takes just a few minutes. All you need is some granulated sugar, cornstarch and a blender or food processor. Add the sugar and cornstarch to the blender or food processor, and blend until it is a fine powder. Depending on the power of your blender or food processor, you may need to blend for up to a minute. Once it is a fine powder, sift it into a bowl to remove any larger pieces. Now you have your own homemade powdered sugar!