Prep the pan: Heat the oven to 300°F (150°C). Lightly grease a 12-cup muffin tin or use a silicone pan.
Place the pan on a sheet tray for easy handling.
Sauté veggies: Warm a skillet with a little olive oil. Soften any raw vegetables (like peppers or mushrooms) for 3–4 minutes. Stir in spinach at the end until wilted.
Cool slightly.
Whisk the base: In a bowl, whisk eggs, Greek yogurt, and milk until smooth. Season with 1/2 teaspoon salt, 1/4 teaspoon pepper, and a pinch of garlic powder or smoked paprika if you like.
Add cheese and mix-ins: Fold in shredded cheese and your cooked add-ins. Avoid overloading each cup—aim for a balanced mix.
Fill the cups: Divide the mixture evenly among the muffin cups, filling about 3/4 full.
Bake gently: Bake for 18–22 minutes, until the centers are just set and barely jiggle. Do not overbake; they’ll firm up as they cool.
Rest and release: Let the egg bites rest 5 minutes.
Run a thin spatula or knife around the edges if using a metal pan. Pop them out and serve warm.