Break the graham crackers in half and place 9 halves in the air fryer. (see note)
Cut the marshmallows in half and place the cut sides down on the graham cracker squares. This helps the marshmallows cook more evenly and prevents them from flying around the air fryer.
Cook at 370 degrees F for 4 minutes.
Remove from the air fryer and immediately add the chocolate squares on top of the marshmallows and top with the other half of the graham crackers that weren’t put in the air fryer. Serve immediately.
Notes
I use a Cosori 5.8qt air fryer - different sized air fryers may be able to hold more or less. If your air fryer holds less, you can cook the s'mores in batches.
If you’re making multiple batches, don’t cut the marshmallows in half until you’re ready to put them on the graham crackers otherwise they will lose their stickiness.
If you want really gooey s’mores, you can air fry for 3 minutes, then add the chocolate and air fry for 1 minute more. However, you do risk a messier air fryer and it makes it more difficult to remove them from the air fryer.