In a small bowl, combine the soy sauce, rice wine vinegar,
brown sugar, olive oil, mustard powder, ginger, black pepper, and garlic to
make a marinade.
Place the fillets in a shallow baking dish and pour the
marinade over them. Cover the baking dish and marinate for at least 1 hour in
the refrigerator, turning the fillets occasionally to keep them coated in the
marinade.
Preheat the air fryer to 190°C. Spray the two air fryer
baskets lightly with cooking spray.
Shake off as much marinade as possible from the fillets and
place them, skin-side down, in the two air fryer baskets in a single layer.
Air fry for 15 to 20 minutes for well done. The minimum
internal temperature should be 65°C at the thickest part of the fillets.
