If desired, spread a little mustard on one side of each slice of bread.
On one side of 4 slices of bread, place a slice of cheese, then a slice of ham, and finally another slice of cheese. Top with the remaining slices of bread to form 4 sandwiches.
Spread a little softened butter on the outside of each sandwich.
Preheat your air fryer to 350°F (180°C).
Carefully place the sandwiches in the preheated air fryer basket. Make sure they do not overlap.
Cook the sandwiches in the air fryer for about 5 to 6 minutes, turning halfway through, until they are golden brown and the cheese is melted.
Remove the sandwiches from the air fryer using tongs.
Let the sandwiches cool slightly before cutting them diagonally to serve.
