How to Make It
In a sturdy, large resealable plastic bag, combine 1 cup of the wine with the meat, garlic, sliced carrot, shallots, thyme, bay leaves and 1 teaspoon of pepper. Seal the bag, pressing out any air and refrigerate overnight.
Drain the meat and pat dry with paper towels; reserve the thyme and bay leaves. In a large enameled cast-iron casserole, heat the oil until shimmering. Season the meat with salt and pepper. Add half of the meat to the casserole and cook over moderately high heat until browned all over, about 10 minutes; reduce the heat to moderate if the meat starts to brown too quickly. Using a slotted spoon, transfer the meat to a plate and brown the remaining beef.
Return the first batch of meat to the casserole. Add the carrot chunks, celery, parsnips, onion, green peppercorns, rosemary and the reserved thyme and bay leaves. Cook, stirring frequently, until the vegetables are barely softened, 7 minutes. Add the remaining 1 cup of wine and cook until reduced to about 1/3 cup, about 10 minutes. Add the tomatoes and veal stock and season with salt and pepper; bring to a boil. Cover the daube and simmer over low heat until the meat is tender, about 2 hours.
Strain the daube in a colander set over a heatproof bowl; discard the thyme, rosemary and bay leaves. Return the braising liquid to the casserole and simmer over moderate heat until slightly reduced, about 10 minutes.
Meanwhile, in a small bowl, mix the butter with the flour until a paste forms. Whisk the paste into the simmering braising liquid and cook until thickened, about 5 minutes. Return the meat and vegetables to the casserole, season with salt and pepper and cook until heated through. Spoon the Celery Root Puree into deep bowls. Ladle the beef on top and serve.