In a large mixing bowl, crack the eggs and whisk them together with the milk, garlic powder, dried oregano, salt, and pepper until well combined.
Add the chopped spinach, diced bell pepper, halved cherry tomatoes, shredded cheese, and chopped green onions to the egg mixture. Stir gently to combine.
Lightly spray a muffin tin with olive oil to prevent sticking.
Pour the egg mixture evenly into the muffin tin cavities, filling each about 3/4 full to allow for rising.
Bake in the preheated oven for 18-20 minutes, or until the egg muffins are puffed up and a toothpick inserted in the center comes out clean.
Once done, remove from the oven and let them cool in the tin for 5 minutes before gently running a knife around the edges and transferring them to a wire rack to cool completely.
Enjoy them warm or store them in an airtight container in the refrigerator for up to a week. They can be reheated in the microwave for a quick breakfast!
Notes
Serve warm or store in an airtight container in the refrigerator for up to a week. Can be reheated in the microwave.