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