Preheat your air fryer to 300°F (150°C) for about 5 minutes.
In a small bowl, combine the melted butter and optional vanilla extract. Brush this mixture lightly over the broken sides of the graham cracker halves.
Lay half of the graham cracker pieces on a heat-safe plate that fits in your air fryer basket.
Sprinkle a generous amount of chocolate chips on each graham cracker half.
Top each with a mound of mini marshmallows. You can adjust the amount based on your preference for marshmallow indulgence!
Place the plate in the air fryer basket and cook for 5-7 minutes. Keep a close watch to prevent burning; you want the marshmallows to puff up and turn golden.
Carefully remove the plate from the air fryer with oven mitts, as it will be hot.
Place the remaining halves of the graham crackers on top of the melted marshmallows and chocolate to create sandwiches.
Let the s’mores sit for a minute to allow the chocolate to melt further, then serve warm.