1. Tie celery, rosemary sprig, thyme, bay leaves, and garlic in a small piece of cheesecloth to make a bouquet garni; set aside.
2. Heat a wide, heavy-bottomed pan over medium heat until hot.
3. Melt butter, and brown meat in two batches, taking care not to crowd the pieces or they will steam and not brown; transfer meat to a bowl using a slotted spoon and set aside.
4. Add onions; cook until slightly softened, about 8 minutes.
5. Return meat to pan and sprinkle flour over the meat and onions, cook about 1 minute, stirring often.
6. Add wine, and bring to a boil, scraping the bottom of the pan to loosen the brown bits.
7. Add the stock and bouquet garni, bring to a boil, cover, and cook on low heat until meat is tender, about 1 1/2 hours.
8. Remove the lid after 1 hour; add carrots, and cook, uncovered, for the last 30 minutes.
9. Season with salt and pepper.
10. Place rutabagas and potatoes in separate saucepans; cover with cold, salted water.
11. Bring to a boil and simmer until tender, 30 to 40 minutes for the rutabagas and 25 minutes for the potatoes.
12. Drain; return to the saucepans to dry out any moisture from the vegetables for a few minutes.
13. Put the rutabagas and potatoes through a food mill fitted with a fine disk, or ricer, or mash by hand.
14. Add butter, as desired, and enough hot milk to make a creamy puree.
15. Season with salt and pepper; stir in chopped rosemary.
16. Preheat oven to 350°F
17. Remove bouquet garni; transfer stew into a deep 2-quart baking dish.
18. Top with puree; dot lightly with butter.
19. Bake 1 hour, or until top is brown and crusty.
20. Serve hot.