We set out to achieve a cookie that was crisp at the edges, chewy in the middle, and full of rich toffee flavor. The result? One of our most popular recipes of all time. Our perfect chocolate chip cookie recipe had to produce a cookie that would be moist and chewy on the inside and crisp at the edges, with deep notes of toffee and butterscotch to balance its sweetness. Melting the butter gave us the chewiness we were looking for. Cutting back on the flour and eliminating an egg white also improved texture and brought the brown sugar flavor to the fore. To give our chocolate chip cookie recipe the crisp edges and toffee flavor we wanted, we let the sugar dissolve in the batter for 10 minutes, then baked the cookies at a high temperature so the edges darkened while the centers stayed soft.