Preheat your air fryer to 400°F (200°C) for 3 minutes.
Slice the potatoes into even 1/4-inch rounds. Pat them dry with a paper towel to remove surface moisture.
Season the potato slices in a large bowl. Toss with olive oil until evenly coated, then add the garlic powder, oregano, smoked paprika, salt, and pepper, and toss again. Do not add the Parmesan yet.
Arrange the potato slices in a single layer in the air fryer basket. Cook in two batches if needed for a full basket — overcrowding prevents crisping.
Air fry at 400°F for 8 minutes, flipping the potatoes halfway through with tongs.
Add the Parmesan by sprinkling it evenly over the partially cooked potatoes. Return to the air fryer and cook for another 3–4 minutes, until the cheese is melted, crisped, and golden brown.
Serve immediately. Transfer to a plate, sprinkle with fresh parsley if using, and enjoy while the crust is at its crispiest.