Preheat your oven to 375°F (190°C). Coat a 12-cup muffin pan with cooking spray.
In a medium bowl, mix the eggs, egg whites, spinach, Italian seasoning, salt, and pepper until well blended.
Pour the egg mixture into the prepared muffin cups, filling each about ¾ of the way.
Sprinkle the chopped sun-dried tomatoes and crumbled feta cheese over the egg mixture in each muffin cup.
Bake in the preheated oven for 15-18 minutes, or until the egg muffins are set and slightly golden on top.
Let the muffins cool in the pan for 5 minutes. Use a small spatula or butter knife to loosen the sides of each egg cup. Lift each egg muffin cup out of the pan and enjoy!
