Finely chop the onion. Place all the ingredients into a bowl and mix well. Shape the mixture into 10 to 12 balls.
Preheat the Airfryer to 200°C.
Place the meatballs in the Airfryer basket and slide the basket in the Airfryer. Set the timer for 7 minutes.
Transfer the meatballs to an oven dish, add the tomato sauce and place the dish into the basket of the Airfryer. Slide the basket into the Airfryer. Turn the temperature to 160°C and set the timer for 5 minutes to warm everything through.
Chef’s tip: For a great snack, you can serve the meatballs without the tomato sauce.