Preheat the oven to 350°F (180°C), or use an air fryer.

In a bowl, whisk the eggs together with the milk, salt, and pepper.

Add the chopped vegetables and cheese, then stir to combine.

Lightly grease a muffin tin with oil.

Pour the egg mixture into the cups (about 3/4 full).

Bake for 15 to 20 minutes, until the muffins are set and golden.

Let them cool for a few minutes, then remove from the tin.