Step 1: Scrub and Pierce: Scrub the potato skins with a stiff brush, then pierce the surface 8–10 times with a fork (piercing releases steam and prevents bursting).
Step 2: Rub With Oil: Dry the skins, then brush on a thin layer of olive oil and scatter the black pepper and garlic powder. The oil builds the crisp skin — but don't overdo it.
Step 3: Load the Basket: Place the potatoes in the basket with no overlap. Set the air fryer to 200°C (400°F) for 40 minutes (medium potatoes; large ones 45–50 minutes).
Step 4: Flip at the Halfway Mark: At 20 minutes, pull the basket out and flip the potatoes so all sides crisp evenly.
Step 5: Check and Serve: They're done when a fork slides easily through the center (skin wrinkled and crisp, gently springy when squeezed). Split open, scatter the optional salt substitute, and top with lemon or salt-free Greek yogurt.