In a skillet over medium heat, brown the ground beef for about 7-10 minutes until fully cooked and no longer pink. Drain any excess fat.

Mix in the chopped onion, ketchup, mustard, and a pinch of salt and pepper to the beef. Cook for an additional 3-4 minutes until the onion is tender.

Take a tortilla and place half a slice of cheddar cheese on it. Spoon a generous amount of the beef mixture onto the cheese and fold the tortilla tightly around the filling.

Preheat your air fryer to 375°F (190°C) for about 5 minutes.

Place the assembled wraps in the air fryer basket. Air fry for 5-7 minutes, flipping halfway through.

Carefully remove the wraps from the air fryer and let them cool for a minute. Serve warm.