Pro Tips: The #1 secret to bakery-style cookies is chilling the dough for at least 30 minutes (up to 24 hours). This prevents spreading and deepens the flavor. Do not overmix after adding the flour—mix just until combined for tender cookies. For the chewiest cookies, slightly underbake them; they'll continue to set on the hot baking sheet. Always use real butter for the best flavor and texture. Measure your flour correctly by spooning it into the cup and leveling it off.