Spray a 12-cup muffin pan heavily with cooking spray, and preheat the oven to 350 degrees F.
In a large bowl, combine the eggs, ham, cheese, onions, and peppers.
Pour ⅓ cup of the egg and ham mixture into each of the greased muffin cups. Place the muffin pan into the oven and cook for 18-22 minutes, or until the eggs are set.
Remove the pan from the oven, and allow the egg muffins to cool in the pan for 5 minutes. Carefully run a knife around each muffin to loosen and remove.
Serve hot! Store any leftovers in an airtight container in the refrigerator for up to 3 days.
The calories listed are an approximation based on the ingredients and a serving size of one (1) egg muffin. Additionally, it does NOT include the extra diced green onions seen in the photos. Actual calories will vary.