Prepare the kale: Rinse the kale thoroughly under cold water and shake it dry. Tear the leaves away from the tough central stalks into bite-sized pieces, roughly the size of a £2 coin. You want them large enough to hold seasoning but small enough to crisp evenly. The leaves should feel dry to the touch—any water left on them will steam rather than crisp.

Dry the kale completely: This is the most critical step. Spread the torn leaves on a clean tea towel or use a salad spinner to remove every last drop of moisture. When you press a leaf between two pieces of kitchen paper, no water should transfer. Wet kale creates soggy chips that taste like steamed cabbage.

Season the leaves: In a large bowl, combine the olive oil, salt, garlic powder, onion powder, smoked paprika, and nutritional yeast. Add the dry kale and toss with your hands, massaging the oil and seasoning into every crevice. The leaves should look glossy but not dripping—you're aiming for a light coating that clings to the surface. You'll hear a faint rustling sound as the oil coats the crinkles.

Preheat the air fryer: Set your air fryer to 180°C (350°F) and let it run for 3 minutes. A preheated air fryer creates an immediate blast of heat that sets the exterior of the kale, locking in the crispness. The basket should feel hot when you open it.

Arrange in a single layer: Place the seasoned kale in the air fryer basket in a single, even layer. It's tempting to pile it all in, but overcrowding leads to steaming. The leaves should have space between them—imagine they're sunbathing, not huddling for warmth. Work in batches if needed.

Air fry the kale: Cook at 180°C for 4 minutes. After 4 minutes, pause the air fryer and shake the basket vigorously. The leaves will have shrunk by half and started to curl at the edges. Return to the air fryer for another 2-4 minutes, checking every minute after the 6-minute mark. The chips are done when they are crisp to the touch, with a deep green colour and a delicate, papery texture. You'll hear a light crackle when you press on them.

Rest before serving: Transfer the chips to a cooling rack or a wide plate in a single layer. Do not stack them while hot. Let them rest for 5 minutes—this allows any residual moisture to evaporate and the structure to set. The chips will sound brittle when you move them, like autumn leaves.

Season again (optional): Sprinkle with a pinch of flaky sea salt and a squeeze of lemon juice if using. The lemon juice adds a bright note that cuts through the richness of the oil. Serve immediately or cool completely for storage.