Preheat oven to 350 degrees.
In a medium bowl, beat eggs, milk, salt, and pepper until blended.
Stir in all other ingredients and mix well.
Spoon about ¼ cup of the mixture into each of the lightly greased muffin holes.
Bake until just set, about 18 to 22 minutes.
Store frittatas in an airtight container in the refrigerator for up to four days. You can reheat one or two frittatas in the microwave for 30-45 seconds, just until warm.
This is a fun recipe for experimenting with different ingredients based on your tastes. You can change the veggies and cheese and add meat for extra protein!