Set the oven to 350 degrees farenheight and coat a muffin tin with 12 cups using oil or spray.

In a bowl, combine eggs, milk, salt, and pepper and whisk until blended.

Evenly mix in the feta and spinach.

Pour the mixture into muffin mugs, leaving about 3/4 empty.

Bake 18 to 22 minutes until golden brown and set. After a few minutes, loosen the edges with a knife to cool.