Prep your air fryer and molds: Preheat the air fryer to 300–320°F (150–160°C) if your model allows. Lightly spray a silicone muffin mold or ramekins with oil. Make sure the mold fits flat in the basket.

Drain watery veggies: If using mushrooms or tomatoes, sauté mushrooms briefly and blot dry; scoop seeds from tomatoes. This keeps the egg cups from turning watery.

Whisk the base: In a large bowl, whisk eggs, milk, salt, pepper, and garlic powder until smooth and slightly frothy. Stir in chopped herbs if using.

Layer the veggies: Divide peppers, spinach, onion, and any optional veggies evenly among the cups. Aim to fill each cup about one-third with vegetables.

Add cheese (optional): Sprinkle a small pinch into each cup. A little goes a long way.

Pour the eggs: Carefully pour the egg mixture into each cup, leaving about 1/4 inch at the top for expansion.

Air fry: Place the mold in the air fryer basket. Cook at 300–320°F (150–160°C) for 10–14 minutes, depending on your machine and cup size. The tops should be set and just barely jiggle in the center.

Rest and release: Let the cups sit for 2–3 minutes to finish setting. Gently release from the mold with a silicone spatula or butter knife.

Taste and adjust: Sprinkle with extra herbs, salt, or pepper if needed. Serve warm or let cool for meal prep.