Creating Quick & Healthy Egg Muffins with Spinach and Feta is straightforward with these easy-to-follow steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C) and lightly grease a muffin tin with olive oil or cooking spray.
2. Whisk Eggs: In a large mixing bowl, crack the 6 eggs and whisk them together until well combined.
3. Add Milk: Pour in ¼ cup of milk to the eggs and whisk until smooth.
4. Incorporate Vegetables: Stir in the chopped spinach, feta cheese, diced bell pepper, and finely chopped onion. Mix well to combine all the ingredients.
5. Season: Add salt, black pepper, and garlic powder to the mixture. Stir until everything is evenly distributed.
6. Fill Muffin Tin: Pour the egg mixture into the greased muffin tin, filling each cup about ¾ full.
7. Bake: Place in the preheated oven and bake for 18-20 minutes or until the muffins are set and slightly golden on top.
8. Check for Doneness: Insert a toothpick into the center of a muffin; if it comes out clean, they are done.
9. Cool and Serve: Allow the muffins to cool for a few minutes in the pan before transferring them to a wire rack to cool completely.

Now you have delightful Quick & Healthy Egg Muffins ready to serve!