Optional Seasonings: 1/4 teaspoons fresh ground black pepper, garlic powder, onion powder, paprika, Old Bay, or ranch seasoning
Do Ahead: Wash and dry potatoes. Using a sharp knife or a mandolin, slice potatoes into strips of even thickness (thinner fries will turn out crisper than thicker ones.) Immediately place sliced potatoes into a bowl of cool water so that they're fully submerged, about 60 minutes to overnight.
Dry: Drain and rinse potatoes well. Using paper towels or clean absorbent cloths, pat-dry all excess moisture from potatoes.
Season: In a bowl, gently toss potatoes with olive oil and salt. Add pepper and any other seasonings, if desired.
Cook: Working in batches, place fries in a single/even layer on rack of air fryer. Be sure fries are not overlapping. Cook 15-20 minutes* or just until golden and crisp (cook time depends on thickness of fries.) While fries are cooking, set your oven to warm setting if you won't be serving the first batch immediately.
Keep Warm: If not serving first batch right away, place them on a baking sheet in warm oven; repeat cooking the remaining fries. As always, fries are best served immediately after cooking.