One very common phrase in baking is the direction to “bake until just set.” This phrase tends to mean slightly different things for different baked goods, although you’ll see the same instruction for brownies, cookies, cheesecakes and custards.
For cookies, baking until just set means that the edges of the cookie should be slightly firm or dry to the touch and the top of the cookie should no longer look wet. In other words, it shouldn’t still feel like raw cookie dough if you gently touch it with your finger. This instruction is most often given with chewy cookies, or fudgy and brownie-like chocolate cookies where you want to make sure that the finished cookie is not overdone and the amount of browning around the edge does not necessarily give you a definitive result on how done it is.
For cheesecakes and custards, where the term is used even more frequently, it is a little more difficult to determine when something is “just set,” although with a little bit of practice, you’ll be able to spot it very easily. Cheesecakes and custards are never cooked until they are firm. Instead, you need to jiggle the pan slightly and see how the batter moves. It will jiggle slightly and evenly over the whole surface, not just at the center. If you’ve ever made jello and seen how it firms up more quickly at the edges than at the center, use that as a reference because that is exactly how cheesecakes and custards set up – from the outside to the center. So, watch to see that the center doesn’t look significantly looser than the rest of the cheesecake when you give the pan a nudge and you’ll have a cheesecake that is done perfectly when you take it out of the oven.