Creating your own Muffin Tin Omelets is simple with these easy-to-follow instructions:

1. Preheat your oven to 350°F (175°C).
2. Grease a muffin tin with cooking spray, ensuring all cups are well-coated.
3. In a medium bowl, crack the eggs and add the milk, salt, and black pepper. Whisk until well combined.
4. Add in the diced bell peppers, chopped spinach, diced onion, diced cooked ham or bacon (if using), and shredded cheese. Stir everything together until evenly mixed.
5. Carefully pour the egg mixture into the prepared muffin cups, filling each about 3/4 full.
6. Place the muffin tin in the oven and bake for 18-20 minutes, or until the omelets are puffed and a toothpick inserted into the center comes out clean.
7. Once done, remove the muffin tin from the oven and allow the omelets to cool for a few minutes.
8. Use a knife to gently loosen the edges of the omelets and pop them out of the muffin tin.

These steps will lead you to delicious, fluffy Muffin Tin Omelets that everyone will love!