Peel and slice the potatoes into thin rounds and cut the onion into thin strips. Place them in your air fryer and cook for 20 minutes at 400°F (200°C), then another 10 minutes at 340°F (170°C). Add a splash of water, salt, and spray with olive oil. This will create some steam and keep them from browning too much.

Heat a nonstick skillet over medium-high heat with a little olive oil. When hot, pour in the potato and egg mixture. Stir briefly with a spatula right after adding it, then let it set for about 4 minutes. Flip the omelette and cook for another 4 to 5 minutes, depending on how well done you like it. Your tortilla is ready!