A number of desserts and sweets are not complete without a final dusting of confectioner's sugar, also known as powdered sugar or icing sugar. Confectioner's sugar is actually granulated sugar which has been mechanically ground into a very fine powder. This powdered form of sugar is commonly used to make cake frostings, sugar glazes, dessert sauces and decorative icings. Confectioner's sugar is also used to provide additional sweetness to fried donuts, funnel cakes and beignets.

Confectioner's sugar is rarely used as a substitute for regular granulated sugar in recipes for a number of reasons. The ratio of confectioner's sugar to granulated sugar would make most recipes cost-prohibitive, for one thing. Confectioner's sugar also does not tolerate long periods of heat, which makes it much more suitable for cold icings and glazes, not heated sauces or custards. Confectioner's sugar also contains up to 3% cornstarch as an anti-caking agent. Some specialty stores do carry confectioner's sugar without such additives, but these are intended primarily for commercial candy companies and bakeries.

The confectioner's sugar sold in most grocery stores has been ground ten times, which explains the 10x designation on the packaging. Some specialty stores carry other grades of confectioner's sugar, such as a 4x or 6x grind. For most purposes, a standard 10x box or bag of confectioner's sugar should perform well enough. The other grades of confectioner's sugar are generally used for specific commercial food products.

It is possible to create confectioner's sugar at home by placing standard granulated sugar in a blender and grinding it into a powder. Homemade confectioner's sugar should be used soon after grinding or stored in a cool, dry area. Powdered sugar will absorb moisture from the surrounding area if left unprotected, so keep it wrapped tightly in a lidded jar or plastic bag. Confectioner's sugar does not need to be refrigerated or frozen, but it should be protected from insects.

Confectioner's sugar can also be kept in an oversized shaker and served along with other breakfast condiments such as syrup, butter and cinnamon. Many people enjoy sprinkling confectioner's sugar over pancakes, french toast or Belgian waffles. A dusting of powdered sugar can also provide some additional sweetness to fruit compotes and gourmet coffee drinks.