Cut cabbage: Use a sharp knife to cut 4 (1-inch/2.5cm thick) wedges of cabbage. (Keep any extra cabbage for another use). Spread the cabbage wedges in a single layer in an air fryer basket (see note 2).
Mix seasonings: In a small bowl, mix together olive oil, whole grain mustard, apple cider vinegar, garlic powder, smoked paprika, salt and pepper.
Brush cabbage: Brush the seasoning mix onto both sides of the cabbage wedges.
Bake and serve: Bake cabbage in an air fryer (no need to preheat) at 375°F (190°C) until crisp on the edges and tender in the middle, 8 to 10 minutes (time varies by air fryer). Serve hot (see note 3).