Season beef with salt and pepper to taste. Sauté in 1 tablespoon of olive oil until browned on all sides. Remove to a plate.
Add wine to the pot and scrape up any browned bits in the bottom. Return beef and any juices to the pan. Add stock and thyme; bring to a boil. Reduce heat and summer 1 ½ to 2 hours, until beef is tender.
Meanwhile, preheat oven to 400. On baking sheet, combine onions, oil and salt and pepper to taste; toss to coat and spread in a single layer. Roast 45-50 minutes.
Drizzle with 3 tablespoons vinegar and roast, stirring occasionally, until onions are dark brown and glazed, 10-15 minutes.
Remove beef from pot and tear into shreds with two forks. Discard any fat or gristle. Return to pot and add roasted onions, cream and remaining vinegar.
Simmer 5 minutes. Do not boil. Season to taste with salt and pepper.