Preheat the oven to 375F. Grease a standard muffin tin with a little oil or non-stick spray.
In a large bowl, whisk together the eggs, garlic powder, salt and pepper. Stir in chopped spinach,feta cheese and diced bell pepper.
Pour the mixture evenly into 8 muffin cups. Bake for 14-16 minutes, until the centres are set. Let cool slightly before removing from the tin. Serve warm.