Line the air fryer basket with a foil tray, silicone liner or small heatproof dish. Add the olive oil, onion, garlic and beef mince. You could also add some grated carrot and chopped bell peppers. Air fry at 180°C for 6-8 minutes, or until the onions start to soften and the mince starts to brown. Stir halfway to break up the mince.