Scrub potatoes and slice each into evenly sized wedges.
Soak wedges in a bowl of cold water for 10 minutes to remove excess starch.
Drain well and pat very dry with towels. Preheat the air fryer to 400°F.
Toss wedges with olive oil in a large bowl until lightly coated.
Combine cornstarch, salt, garlic powder, paprika, onion powder, and pepper. Sprinkle over potatoes and toss until coated.
Arrange wedges in a single layer in the basket without crowding.
Air fry for 10 minutes, shake the basket, then cook 8–10 minutes more until deeply golden and tender.
Serve hot. Sprinkle with dried parsley and Parmesan if using.