Step 1

Heat the air-fryer to 190C. Butter the slices of bread on one side each, then combine the remaining butter with the mustard, cheese and chives, if using. Season with black pepper.

Step 2

Spread the cheese mixture over the plain sides of the bread, then sandwich the ham between the two slices so the buttered sides are facing out. Air-fry for 10 mins, turning once until golden and crunchy on the outside, and the cheese has melted in the middle.