Traditional buttercream frosting is typically made with powdered sugar (also known as confectioners' sugar) rather than granulated sugar. Powdered sugar has a finer texture, which helps create a smooth and creamy frosting. Granulated sugar can be more difficult to dissolve and incorporate into the frosting, resulting in a grainy texture. However, there are variations of frosting recipes that use granulated sugar, such as cooked frostings like Seven-Minute Frosting or Italian Meringue Buttercream, which involve cooking the sugar to dissolve it before adding it to the other ingredients. These frostings can provide a different texture and flavor compared to traditional buttercream.