Preheat oven to 350°.

Heat 1 tablespoon coooking oil a large skillet. Add chopped leek or onion and sauté 2 minutes or until crisp-tender. Add ham and sauté another 3 minutes. Remove from heat and cool 5 minutes. Combine remaining ingredients in a large bowl; stir with a whisk. Add ham mixture, stirring with a whisk.

Spoon mixture into miniature muffin cups coated with cooking spray. Bake at 350° for 20 minutes or until set.