Preheat oven to 350 degrees F.
Generously spray a muffin tin with cooking spray. Set aside.
In a large bowl, whisk together eggs and black pepper until well combined.
Stir in shredded cheese and your mix-ins. We used green pepper, mushrooms, and turkey bacon.
Spoon the egg mixture into the prepared muffin tin, filling each muffin cup about 3/4 full.
Bake at 350°F (175°C) for approximately 20-25 minutes, or until the egg muffins are set and slightly golden.
Let rest for 5 minutes. Run a butter knife around the muffin edges to remove them from the muffin tin.