If you’re looking for a finer texture and extra lightness in your cookies, consider swapping in superfine sugar for granulated. The smaller crystals of superfine sugar, also known as caster sugar, trap more air when the sugar and butter are beaten together during creaming, Rose Levy Beranbaum says in “The Cookie Bible.” The finer sugar also means the dough is less likely to crack during baking. For cookies rolled in sugar before baking, superfine provides a delicate, even coating. If you can’t find it on shelves or don’t want to buy it, just process granulated sugar in the food processor until it’s more finely ground (if you go too far, you’ll end up with something more like confectioners’ sugar). And if you’re substituting superfine for granulated, be sure you are doing so by weight, not volume.