Bread
Cheese
Tomato slices
Butter two slices of bread. Put one slice on top of the other, so that both buttered sides are together in the middle. On top, add slices of tomato and cheese.
Preheat the air fryer to 360 F.
When the air fryer has finished preheating, lift off the top slice of bread with the tomato and cheese, and lay it into the air fryer basket (buttered side down, toppings up). Then place the other slice of bread on top, buttered side up.
Air fry for a total of 6 to 10 minutes; carefully flip sandwich at 4 or 5 minutes to enable even browning.