Question: what is the difference between powdered sugar and icing sugar?
Answer: Icing sugar is simply another name for powdered sugar or confectioners' sugar. While it is a less common name here in the U.S., it makes sense since icing, powdered or confectioners' sugar is so perfect for making icings, frostings and fillings, such as the filling in my Homemade Oatmeal Cream Pie recipe.