Using a large, flat fork, place each cooled cookie on the tines and carefully dip into the chocolate-peppermint coating. Gently turn the cookie, so top/bottom/sides are coated equally, and use a butter knife to remove any excess (you want a smooth, even coating on all sides – not so thin that the cookie shows underneath but not so thick that the cookie is drowning in chocolate). Be prepared: this part can get a little messy, but you’ll get the hang of it in no time.