Caster Sugar

Caster sugar, also known as superfine sugar, is more common outside of the US. It is white sugar that is more finely ground than granulated sugar, but not as finely as powdered sugar. Castor sugar can be used as a 1:1 substitute by weight for granulated sugar. If you have a recipe that calls for superfine sugar and you only have granulated sugar available, place it in a food processor and pulse for 10 seconds.