2. Heat half of the oil in a big pan over low heat. Add the onions and cook them for 5 minutes, covered. Stir occasionally.
3. Add the potatoes and stir while cooking for about 3 minutes. Season with salt and pepper. Remove it from heat and allow to cool to room temperature.
4. In a different bowl, whisk the eggs and season with some salt and pepper.
5. Mix the eggs, bell pepper, potatoes, and zucchini together.
6. Pour the egg-veggie mixture in a baking dish that can fit into your Air Fryer basket. Preheat your Air Fryer to 350 F (175 C).
7. Cook for 30-40 minutes. Sprinkle with mozzarella on the last 15 minutes of cooking time. Allow to cool slightly.