Preheat the air fryer: Set it to 370°F (188°C) for 3 minutes. A short preheat helps the bread crisp fast without over-drying.
Prep the bread: Spread a thin, even layer of softened butter or mayo on one side of each slice. Spread to the edges for even browning.
Assemble the sandwich: Place cheese between the unbuttered sides so the buttered sides face out. Mix cheeses for best melt—try American plus sharp cheddar.
Optional add-ins: If using tomatoes or onions, pat them dry.
Layer them between cheese slices to prevent sliding.
Air fry, first side: Place the sandwich in the basket. If your basket has wide grates, set a small piece of parchment under the sandwich. Cook at 370°F (188°C) for 4–5 minutes.
Flip carefully: Use a spatula to flip.
Press lightly to help the cheese bond and the edges crisp.
Air fry, second side: Cook another 3–4 minutes, until the bread is deep golden and the cheese is fully melted. Peek at 2 minutes to avoid over-browning.
Rest briefly: Let the sandwich sit for 1 minute before slicing. This keeps the cheese from rushing out.
Slice and serve: Cut on the diagonal for maximum cheese pull. Serve with soup, salad, or chips.