Brown butter is one of the simplest upgrades in baking. Butter cooked just past melted turns amber and fragrant, with a depth that is similar to toasted hazelnut and caramel. This recipe builds on that flavor, and it browns the butter in the same cast-iron skillet the cookie bakes in.
The rest stays refined but unfussy. Chopped semi-sweet chocolate and milk chocolate chips are folded into a dough enriched with an extra yolk, then pressed into the skillet and baked until the edges turn crisp and golden while the center stays soft. It goes to the table warm in its pan, crowned with vanilla ice cream and meant to be shared. With National Homemade Cookies Day on October 1, one generous cookie is a worthy alternative to three dozen small ones.

