What to look for
Look for confectioners’ or powdered sugar; the names are usually interchangeable in U.S. recipes. Check the label if a particular starch matters for dietary needs.
Store it thoughtfully
Keep tightly sealed and dry because it readily absorbs odors and humidity. Sift out small clumps just before using.
How to use it
Whisk it gradually into a small amount of liquid for glaze, or beat it into softened fat for frosting. Add liquid by the teaspoon because the mixture loosens quickly.
When you need a substitute
Granulated sugar will feel gritty in uncooked icing. Homemade powdered sugar can vary in fineness and starch content, so use it only when a recipe tolerates variation.
Substitutions change flavor, texture, and sometimes safety or structure. Check the recipe and product labels, especially for dietary needs.