Preheat the oven to 160°C-180°C. Heat a large pan over a moderately high heat, add a little oil. Brown the shanks well on all sides. Remove and place them in a large casserole dish.
Reduce heat in pan and add a little extra oil, the onion and carrot. Cook for 1-2 minutes, stir occasionally. Gradually pour stock, followed by the tomatoes and rosemary and stir until the mixture boils.
Pour over the shanks. Cover the dish tightly with its lid, place in oven. Cook for 2 hours or until shanks are very tender. Turn the shanks occasionally and adjust the heat as it cooks if needed. You may need to add a little more stock or water if it appears too dry.
Pull the meat from the lamb shanks and discard the bones. Pull the lamb into bite-sized pieces and return to the sauce. Combine the breadcrumbs, butter, cheese and extra rosemary and scatter over the lamb mixture. Bake in the preheated oven for 15 minutes, or until the hot and the crumble lightly golden.
