Preheat oven to 350°F. Spray muffin tin with nonstick cooking spray and set aside.
Whisk eggs in a bowl. Add vegetables and cheese into each well of the muffin tin. Each muffin cup can be different.
Pour egg mixture on top of the add-ins, leaving about ¼-inch space at the top.
Bake for 20 minutes or until a toothpick inserted comes out clean.
Serve hot or freeze for later. To reheat, microwave for 30 - 45 seconds.