3 celery ribs, cut diagonally into 1-inch pieces .
1 tsp black pepper .
1 tbsp fresh lemon juice (to taste) .
celery leaves .
6 beef shanks (1 1/2-inch-thick, 6 lbs) .
4 large head of garlic, 1/4 inch of root end cut off & discarded to expose cloves .
1 3/4 c reduced-sodium beef broth (14 fl oz) .
2 c water .
1 1/2-2 tbsps extra-virgin olive oil .
8 fresh thyme sprigs .
2 turkish bay leaves (or 1 California) .
Special equipment .
1 tbsp salt .
3 large carrots, cut diagonally into 1-inch pieces .
2/3 c all-purpose flour
Directions
Step #1 Put oven rack in middle position & preheat your trusty oven to 350°F.
Step #2 Pat shanks dry & rub all over with salt & pepper.
Step #3 Dredge shanks in flour, turning to coat.
Step #4 Heat 1 1/2 tbsps oil in a 12-inch heavy skillet over moderate heat until hot but not smoking, adding 1/2 tbsp oil if necessary, then brown shanks on all sides in 3 batches, 5 to 6 mins per batch.
Step #5 Transfer shanks to a large roasting pan.
Step #6 Add broth & water to skillet & bring to a boil, scraping up brown bits.
Step #7 Nestle garlic (cut sides down), zest, thyme, & bay leaves with celery & carrots around shanks in pan & add broth mixture.
Step #8 Cover up surface with a sheet of parchment paper & tightly cover pan with foil wrap.
Step #9 Transfer to oven & braise until meat is very tender, 2 1/2 to 3 hrs.
Step #10 Skim off & discard fat from cooking liquid & cool mixture completely, uncovered, about 1 hr, then chill, covered, at least 6 hrs.
Step #11 Preheat oven to 350°F (leave rack in middle position).
Step #12 Skim off & discard any remaining fat from surface of pan juices & reheat shank mixture, turning shanks over once, in oven, covered, 1 hr.
Step #13 Discard bay leaf, thyme sprigs, & zest.
Step #14 Transfer shanks & vegetables with garlic to a serving dish & keep warm, covered.
Step #15 If pan juices measure more than 3 c, boil in a cleaned 12-inch skillet until reduced; if less, add water.
Step #16 Squeeze garlic pulp from 1 head into pan juices, discarding skin, & whisk to incorporate.
Step #17 Add lemon juice & salt & pepper to taste.
Step #18 Pour sauce over shanks & serve, along with vegetables & remaining garlic heads.
Step #19 Cooks' note: Braised shank mixture can be chilled, covered, up to 2 days.