In a large shallow dish, combine the vinegar, garlic, and mustard.
Trim excess fat from the lamb and place in the dish; turning to cover with the marinade. Let stand for 30 minutes.
Meanwhile, heat the olive oil in a braising pan on medium heat.
Add the onions and garlic and sauté until onions begin to brown, about 8 minutes.
Add the lamb and sear on both sides. Pour molasses over lamb and continue to brown on both sides.
Add the bay leaf, sage, salt, and beans with their liquid, and water or red wine.
Simmer on low heat until lamb is tender and beans are heated through, about 15– 20 depending on the thickness of the lamb and how well done you like it.
Garnish lamb and beans with pomegranate seeds and parsley.