The Difficulty

• The problem with oversized cookies is that their edges are often overbaked by the time the middle is done. In part, that's a matter of basic physics. Heat conducts through your dough at a given speed, and if there's more dough, it takes longer. You can't change the laws of physics, but you can tilt the scales in your favor. There are a number of ways to alter the baking characteristics of your cookies, so choose the one that makes sense for you.

Time and Temperature

• One of the simplest fixes is to reduce your oven's heat and extend the cookies' baking time by a few minutes. The edges of the cookie will be slower to set and become brown at the lower temperature, but the extended baking time creates more opportunity for the middles to bake completely. This approach is best-suited to oversized but not gigantic cookies, up to 6 or 7 inches in diameter. If you're baking even bigger cookies, you'll need to dip further into your baker's bag of tricks.

Pick a Pan

• You might be deeply attached to the cookie sheets you inherited from your grandmother, but if they're dark in color, they might not be your best choice. Dark-colored sheets tend to transfer the oven's heat to your baking with a gusto that's sometimes inconvenient. For large cookies, it's best to use the kind of heavy, matte-finish aluminum sheets favored by professional bakers. They transfer heat effectively but deliberately, so the bottom and edges of your cookies won't overbake as quickly. If your oven tends to bake too much from the bottom, like some ovens, double the baking sheet. That slows the heat from below, giving the cookie or cookies more time to bake through.

Crossing Your Ts

• If you've already chosen a good pan and turned down your oven's heat, you can still take a few more steps to ensure success. For one, ensure that your dough is as thin as it would be for an ordinary cookie. Sometimes that means refrigerating your cookie dough and slicing it evenly into rounds, which will spread to cover the whole sheet, even if the original is a drop cookie. Another useful technique is to protect the edges from over-baking with a foil cover. Get this ready before you put the cookie in the oven, tearing and folding sheets to make a foil ring around the outer edges of your jumbo cookie. Once the edges brown, open the oven and quickly position the protective ring, then close the oven and finish baking.

You're Doing It Wrong

• Professionals understand one final point: Your cookie shouldn't be all the way set in the middle when you take it out of the oven. If it is, your cookie's overbaked. This doesn't matter much with ordinary cookies, but it's important with giant party-sized versions. When the outer two-thirds of the cookie is set and fully baked, but the middle is still soft, that's usually the right time to pull it out. Let the cookie cool for at least an hour, 10 minutes on the tray, and then 50 on a rack. The middle will set but remain chewy. Transferring the cookie is easiest if you bake it on a sheet of parchment paper.