1. Preheat oven to 375 degrees. Generously season beef with salt and pepper. Dredge beef in flour; shake off excess.

2. Wrap parsley, thyme, allspice, and peppercorns in cheesecloth, and tie with kitchen twine to form a bouquet garni.

3. Heat 3 tablespoons oil in a Dutch oven or large ovenproof saucepan over medium-high heat. Working in batches, brown beef, 3 to 4 minutes per side, adding more oil (up to 2 tablespoons) as needed. Transfer beef to a bowl.

4. Add 1 tablespoon oil to fat in pot. Stir in leeks, celery, and garlic; cook, stirring occasionally, until softened, about 7 minutes. Add stout; cook, scraping up browned bits from bottom of pot.

5. Return beef to pot. Add stock, bouquet garni, zest, and enough water to cover. Season with salt and pepper. Bring to a boil over medium-high heat. Cover pot; transfer to oven. Braise beef 2 hours.

6. Add potatoes and carrots. Cover pot; braise 1 hour more. Discard the bouquet garni. Garnish stew with parsley.