A retortable container is formed with an opening formed defined by a projecting rim. The rim includes an external surface and securing structure formed thereon. A flexible membrane is sealed to the rim and closes the opening. A closure is provided having a molded plastic tubular ring and a separately formed molded plastic disk. The tubular ring includes an overlapping flange at a top and directed inwardly towards an inwardly positioned open area. The skirt includes an engagement structure for securing the closure to the external surface of the rim. The disk is separately attached to the ring within the open area after the retort process is applied to the sealed bottle.