Stir together the salt, pepper, garlic powder, and Italian seasoning.
Wash and dry the potatoes, then place in a single layer in air fryer and roast for 17-20 minutes. After 10 minutes of cooking, use tongs to rotate the potatoes to ensure even cooking.
Remove potatoes from the air fryer and place them on a sheet pan. Smash each potato gently with the back of measuring cup or the bottom of a large glass.
Brush one side of the potatoes with olive oil and sprinkle with the spice mixture. Flip them over and brush the other side with olive oil and sprinkle with the spice mixture. If you're using parmesan, sprinkle it on top of the potatoes now.
Return the potatoes to the air fryer and cook for another 15-20 minutes, until they're golden brown and crispy.