Spray basket with cooking spray or use an air fryer liner.

Preheat air fryer to 350F.

Wash potatoes and then dry them REALLY well. Super dry. 

Lay down two wooden spoons on the cutting board about two inches apart. See photo. 

Set one potato on the spoons lengthwise so the fat part of the potato is facing you. 

Slice potatoes into 1/4" sections but leave about 1/2" uncut on each long end. Repeat for the other potato. Set them aside.

In a small bowl mix the olive oil or melted butter, garlic, salt and pepper. 

With a pastry brush, liberally coat the potatoes with the mixture, getting it in between the slices.

Using tongs, gently place the potatoes in the air fryer basket. 

Bake for 20 minutes.

Open the air fryer and baste potatoes with additional olive oil mixture, coating the inside of the cuts again.

Cook for an additional 10 to 15 minutes, especially if these are very large potatoes. 

Using tongs in one hand and a spatula in the other, GENTLY remove the potatoes from the air fryer and immediately sprinkle with parmesan cheese. 

Serve any additional sides such as sour cream, bacon bits, green onion, or chili on the side so you don’t cover the beauty of the hasselback cuts.