Spray cups of a muffin tin with nonstick cooking spray.
Preheat oven to 375 degrees.
Whisk eggs, milk, salt and pepper together in a measuring cup with a spout.
Divide your optional ingredients evenly into the tins.
Pour enough egg mixture into each cup to come to the top.
Sprinkle with a bit of grated cheese, if desired.
Bake for about 15-20 minutes. Makes 12.