Preheat oven to 300°F. Pat the beef dry with paper towels and sprinkle with salt and pepper.
Place a heavy, ovenproof pot over medium-high heat, add a generous drizzle of oil and brown the meat in batches, without crowding the pan.
Add the onion and cook for 3-4 minutes, until soft and starting to loosen the browned bits in the bottom of the pan.
Add the garlic and tomato paste and cook for another minute.
Add the stock and wine, enough to just cover the meat. Add the thyme, cover and cook for 2 1/2 hours, until the meat is very tender.
Add the potatoes, carrots and parsnips, stir to coat everything well and return to the oven for another half hour, until the vegetables are tender.