Preheat oven to 325°F.
Bring meat to room temperature and season with salt and pepper. In a shallow dish, combine the flour with ground sage and granulated garlic and onion. Dredge meat to lightly coat.
Heat oil in a Dutch oven, 4 turns of pan, over medium-high heat and brown meat on all sides in two batches; remove to plate. Add onion, carrot, celery, garlic, thyme, bay, salt and pepper to the pan and sweat 5 minutes. Add tomato paste, stir a minute, then add cider or beer and stir a minute. Add stock and reserved beef; cover and transfer to oven for 1 1/2 hours.
Remove pot from oven and add butternut squash and leeks. Stir, return to oven for another 45 minutes. Place stew on stove, keep warm and covered. Before serving, adjust seasoning and remove bay leaf.
In a pot, cover parsnips and potatoes with water by 3 to 4 inches. Bring to a boil, salt water and cook to tender, 15 minutes. Drain, return to hot pot and mash with chicken stock, milk and cheese. Season with salt, pepper, nutmeg and mustard.
Serve stew in shallow bowls over the mashed potatoes and parsnips.