Place the giblets, neck bone, broth, carrots, celery & shallots in a large saucepan; bring to a boil. Reduce heat; cover and simmer for 1-1/4 hours.
Strain and discard giblets, neck bone and vegetables; set cooking juices aside. In another large saucepan, combine cornstarch and water until smooth; stir in the drippings and bouillon until smooth. Gradually stir in the reserved cooking juices. Bring to a boil; cook and stir for 2 minutes or until thickened. Season with pepper.