Scrub the potatoes clean and blot dry with a paper towel.
Use a fork to pierce holes in the potatoes. Brush with oil and sprinkle on salt. Air fry at 400F for about 40 minutes, or until fork tender. Let cool enough to handle. (You can also bake the potatoes in the oven at 400F for 50-60 minutes).
Cut potatoes in half lengthwise and scoop out the flesh, leaving about 1/4 inch of flesh in the potato skins.
Place the skins back in the air fryer basket, skin side up. Air fry at 400F for 3-4 minutes to crisp up the skin again.
Carefully remove the skins from the air fryer basket and place them flesh side up on a work surface.
Add a tablespoon of marinara to each potato, spreading it out over the potato flesh. Top each one with 2 tablespoons of mozzarella cheese and 2 slices of pepperoni. (You can use more if your potatoes are larger).
Air fry at 400F for 4-5 minutes, or until the cheese has melted and the pepperoni is crispy.
Serve with more marinara and some chopped fresh parsley or basil.
Notes
Be careful not to overbake your potatoes as the skins will be tough and chewy instead of crispy.
When scooping out the flesh, leave about 1/4 inch of flesh on the skins. This will help keep the skins sturdy enough to hold up to all of the toppings.
This recipe was tested in a 5.8 quart air fryer and fit 8 potato skins (from medium-sized potatoes). If you have a smaller air fryer, you may wish to half the recipe or air fry in batches.