Lamb shank can be just as tender as leg of lamb if marinaded before grilling. I rub a two pound shank with granulated garlic and soy sauce, no salt, then white pepper, then soak overnight in tomato juice. While the shank is on the grill, I cook quartered potatoes and green pepper slices, onion slices, celery slices and carrot slices in the leftover marinade. I save the marinade to make tomato soup with the leftover bone from the shank by simmering an hour. Bones will be soft enough to go to the dog.
