Chilling the dough allows the flour to properly hydrate and the flavors to meld together. Since we're using brown butter, it's always best to chill for at least 30 minutes to really enhance the warm, nutty flavor. If you have the patience, chilling overnight is best. If your dough is too hard, leave it on the counter for a few minutes until it's just loose enough to scoop out. Make sure it doesn't thaw too much or your cookies could spread really thin.