Preheat oven to 400 F.
Spray muffin tin with cooking spray or use silicone muffin tin. Set aside.
If using optional ingredients, prepare them ahead as needed (for example, diced jalapeno, cooked bacon, onion, peppers, broccoli, shredded cheese). Set aside.
In a medium bowl, combine eggs, egg whites, salt and pepper. Whisk until combined.
Stir in any optional ingredients and/or seasonings.
Pour mixture into prepared tins and fill to about 2/3 full.
Bake 12 to 15 minutes, or until egg is set.