Wash the cavolo nero thoroughly and pat the leaves completely dry. This is important for getting them really crispy.
Remove the tough central stalks and tear the leaves into bite-sized pieces.
Place the leaves in a large bowl and drizzle over the olive oil. Gently massage the oil into the leaves, making sure they're lightly coated.
Sprinkle over the salt, spices and a little black pepper and toss to combine.
Spread the cavolo nero in a single layer on an air fry tray, or baking tray. Don't overcrowd the leaves. Cook it two batches if you have to!
Air-fry at 200C for 5 minutes, or oven bake at 200C for 5 minutes, checking regularly towards the end, until the leaves are crisp and crunchy.
Remove from the air fryer or oven and leave to cool for a couple of minutes. They'll become even crispier as they cool.