Wash and scrub the russet potatoes thoroughly. Using a sharp knife, slice the potatoes crosswise into thin slices—about 1/8 inch thick—stopping just before cutting all the way through. (Tip: Place chopsticks on either side of the potato to prevent the knife from going through.)

Drizzle olive oil over the potatoes, using your fingers or a brush to make sure it gets between the slices. Sprinkle with garlic powder, salt, and pepper, gently opening the slices to let seasoning inside.

Preheat your air fryer to 375°F (190°C). Place the potatoes in the air fryer basket and cook for 25–30 minutes, checking around the 20-minute mark. The slices should start to fan out and crisp up on the edges.

Carefully remove the potatoes and brush with melted butter. Then, sprinkle the shredded cheddar and mozzarella over and in between the slices. Return to the air fryer and cook for an additional 3–5 minutes, until the cheese is bubbly and melted.

Remove from the air fryer and top with chopped chives or green onions if desired. Serve immediately while hot and cheesy!