Preheat oven to 425 degrees.
Place eggs in a medium sized bowl. Beat with a fork.
Add milk, cheese, salt and ground black pepper (as preferred). Stir together.
Spray muffin tin (6 cups) with vegetable oil cooking spray.
Fill each cup with egg mixture. Add 4 pieces of chopped/cooked smoked sausage (optional).
Reduce oven temperature to 375. Bake 15 minutes. Muffins will rise dramatically while baking and... deflate dramatically while cooling.
Serve hot. Or, cool completely. Placed cool egg muffins in a zippered bag or lidded container. Refrigerate up to 3 days.
To warm, place in microwave for 5 seconds. Or, warm in a preheated (400) oven for 5 minutes.