Prep the air fryer and cups: Preheat your air fryer to 325°F (163°C) if it has a preheat setting. Lightly spray silicone muffin cups or a metal muffin tin that fits your air fryer basket.
If using a metal tin, spray well to prevent sticking.
Whisk the egg base: In a large bowl, whisk eggs, milk, salt, pepper, garlic powder, and smoked paprika until smooth and slightly frothy.
Prep the mix-ins: Finely chop the turkey, onion, pepper, and spinach. Pat the turkey dry if it’s deli meat to avoid extra moisture.
Combine gently: Stir the turkey, onion, pepper, spinach, herbs, and cheese into the egg mixture. Fold to distribute evenly without overmixing.
Fill the cups: Divide the mixture among 10–12 muffin cups, filling each about 3/4 full.
Leave a little headspace so they can puff without overflowing.
Air fry in batches: Arrange cups in the basket with space between them for airflow. Cook for 10–14 minutes, depending on your air fryer model and cup size. The muffins are done when the centers are set and the tops are lightly golden.
Check doneness: Insert a toothpick into the center.
It should come out clean, with no wet egg. If needed, add 1–2 more minutes.
Cool slightly and release: Let muffins rest for 3–5 minutes to firm up, then gently loosen edges if needed and remove from cups.
Serve or store: Enjoy warm right away, or cool fully on a rack before transferring to storage.