Heat oil in a 4- to 5-quart Dutch oven over medium-high heat. Add bacon and cook, stirring often, until lightly browned, 3 to 5 minutes. Add onions, carrots and celery; cook, stirring often, until the vegetables are softened and lightly browned, 8 to 10 minutes. Add broth, wine, thyme, bay leaves and orange zest. Bring to a boil.

Rinse beef with cool water to remove any bone bits. Place the beef in a 5- to 6-quart slow cooker and turn heat to high. Carefully pour the hot vegetable mixture over the beef. Put the lid on and cook until the beef is falling-apart tender when prodded with a fork, 6 to 7 hours.

Preheat oven to 350 degrees F. Using a slotted spoon, transfer the cooked beef to a bowl. Lift out the bones. Scoop marrow out and add to the meat, if desired; discard bones. Break the meat into 2- to 3-inch chunks with a spoon. Cover and keep warm.

Discard the bay leaves and orange zest from the sauce; skim fat. Pour the sauce into a large skillet. Bring to a boil over high heat. Boil, skimming froth from time to time, for about 20 minutes, to intensify flavors and thicken slightly. Season with pepper. Add the beef and heat through. To serve, ladle the stew into bowls and sprinkle with watercress (or parsley). Baked Beef Stew variation: Total: 4 1/4 hours Preheat oven to 350 degrees F. In Step 1, use only 1 1/2 cups broth and 1 1/2 cups red wine. In Step 2, place beef and vegetables in a Dutch oven, cover and bake for 3 to 3 1/2 hours. Skim fat. Discard the bay leaves and orange zest. Lift out the bones, scoop marrow and add, if desired; discard the bones. Break the meat into chunks. Blend 2 tablespoons cornstarch with 1/4 cup water; stir into the stew. Return the pan to the oven and bake, uncovered, stirring occasionally, until bubbling, 25 to 30 minutes.

Note: If you cannot find beef shank, substitute cubed stewing beef.

MAKE AHEAD TIP: Cover and refrigerate for up to 2 days or freeze for up to 3 months. Thaw in the refrigerator, if necessary, and reheat on the stovetop, in a microwave or in the oven.