1. Put oil in a large deep skillet or casserole that can be covered later and turn heat to medium-high. Add shanks sprinkling them with salt and pepper. When pieces are deeply browned on one side add thyme garlic onion half the celery and half the carrots and more salt and pepper to skillet. Continue to brown stirring occasionally. 2. Add wine and let mixture bubble for about a minute; cover and adjust heat so that mixture simmers steadily. Cook for about an hour. 3. Add remaining vegetables to pan; zest lemon and add zest as well. Continue to cook until lamb is very tender and vegetables soft another 30 to 45 minutes. (You can prepare dish up to this point in advance; let sit for a few hours or cover and refrigerate for up to a day before reheating and proceeding.) 4. When lamb is done juice lemon and add juice to sauce. Taste adjust seasoning and serve garnished with parsley.