Superfine sugar has a finer crystal than regular white, granulated sugar. It is also known as caster sugar. It dissolves easily into batters, and it gives baked goods a light texture and fine crumb. It is often called for in recipes for meringues and angel food cakes.
While superfine sugar can be used in recipes that call for granulated sugar, using granulated sugar in a recipe that calls for superfine sugar may not yield good results. Superfine sugar can be easily made at home by pulsing granulated sugar in a food processor for about a minute until the crystals are fine. Superfine sugar is not the same as powdered sugar.