Preheat oven to 325° and coat a tart or mini muffin tin thoroughly with nonstick cooking spray. Drain artichoke hearts, reserving 1/2 cup of the liquid marinade. Chop artichokes into small pieces and set aside. In a small sauce pan, heat the reserved liquid marinade, onion and garlic over medium heat until all liquid is absorbed and vegetables are soft. In a large bowl, beat eggs and add in onion mixture, bread crumbs, oregano, salt and pepper. Slowly blend in cheese and artichokes. Spoon mixture into the greased pan and cook for 15-20 minutes or until completely set. Allow tartlets to cool completely in the pan on a wire rack. Once cooled, serve or cover and store in the refrigerator for later use.