Preheat oven to 325. Oil or spray a muffin tin with non-stick cooking spray.
Add butter or oil to a small pan. Fry onion and peppers for a few minutes until translucent and beginning to change color.
Line muffin tin with ham slices. I sliced my ham in half because it made it easier to line the cups with halves.
In a measuring bowl, combine vegetables, chopped ham, and eggs. Mix well.
Spoon or pour mixture into your ham cups.
Bake for 25-30 minutes or until tops begin to turn golden brown. Cups should easily slide out of the muffin tin.