2Wash and dry the potatoes. Using a sharp knife, make thin, close cuts (every 2-3 mm) without cutting all the way through the bottom. You can place chopsticks or wooden spoons alongside the potato to prevent cutting through.
3In a small bowl, mix the grated Parmesan, chopped rosemary, truffle oil, olive oil, salt and pepper.
4Gently fan the potato slices and insert some of the Parmesan mixture between each cut.
5Place the potatoes in the air fryer basket in a single layer without overlapping. Cook at 180°C for 25 minutes until golden and crispy.
6Serve immediately, sprinkled with extra Parmesan and fresh rosemary if desired.