Preheat and prep the tin: Heat your oven to 350°F (175°C). Lightly grease a 12-cup muffin pan with cooking spray or brush with olive oil. Make sure to coat the sides well so the eggs release easily.

Chop the vegetables: Dice bell peppers and onion, halve the cherry tomatoes, and roughly chop the spinach. Pat the tomatoes dry with a paper towel to reduce extra moisture.

Whisk the eggs: In a large bowl, whisk eggs with milk, garlic powder, smoked paprika, salt, and pepper until smooth and slightly frothy. Stir in the herbs.

Add cheese and veggies: Fold the shredded cheese, peppers, onion, spinach, and tomatoes into the egg mixture. If your muffin cups are small, you can divide the veggies among the cups first and then pour the egg mixture over them to control portions.

Fill the muffin cups: Divide the mixture evenly between the 12 cups, filling each about 3/4 full. Give the pan a gentle tap on the counter to release any air bubbles.

Bake: Place in the center of the oven and bake for 18–22 minutes, until the tops are set and lightly golden around the edges. A toothpick should come out mostly clean with a few moist crumbs.

Cool and release: Let the muffin cups cool in the pan for 5 minutes. Run a thin spatula or butter knife around the edges to loosen, then lift out and transfer to a rack.

Serve or store: Enjoy warm, or let cool completely before storing. Add hot sauce, salsa, or a dollop of Greek yogurt if you like.