01 - Whisk together eggs, milk, salt, pepper, and Italian herbs in a medium bowl until completely smooth and well combined.
02 - Add cherry tomatoes, spinach, bell pepper, onion, zucchini, and cheese (if using) to the egg mixture. Stir gently to distribute evenly.
03 - Preheat the air fryer to 350°F for 3 minutes before cooking.
04 - Brush a 7-inch round oven-safe pan or cake tin thoroughly with olive oil to prevent sticking.
05 - Pour the egg and vegetable mixture into the prepared pan, ensuring ingredients are evenly distributed.
06 - Place the pan in the air fryer basket. Cook at 350°F for 12 to 15 minutes until the center is completely set and the top is lightly golden.
07 - Allow the frittata to cool for 2 minutes before slicing into wedges. Serve warm.