Preheat. Preheat your air fryer to 370°F for 3–5 minutes.

Assemble the sandwich. Spread butter evenly on one side of each slice of bread. Place one slice in front of you, butter-side down. Layer the cheese evenly on top, keeping it slightly away from the edges. Top with the second slice of bread, butter-side up. Gently press the sandwich together. Insert a toothpick straight down through the center to secure it. (This prevents the top slice from shifting around once the air starts circulating!)

Air fry. Place the sandwich in the air fryer basket in a single layer. Air fry at 370°F for 4–5 minutes. Carefully flip the sandwich, then cook for another 3–4 minutes, until both sides are deeply golden brown and the cheese is fully melted. Cook time will depend upon the type and thickness of bread that you use, so just keep an eye on things.

Rest and serve. Remove from the air fryer. Remove the toothpick, slice, serve and enjoy!