Question: To allow the cookie to firm up after cooking
Options:
Cover the layered cookie in plastic wrap  and carefully place it in the  refrigerator overnight (or for several hours if you are making this in the morning.
Cover the layered cookie in plastic wrap  and carefully place it in the oven overnight (or for several hours if you are making this in the morning.
Answer: Cover the layered cookie in plastic wrap  and carefully place it in the  refrigerator overnight (or for several hours if you are making this in the morning.