Preheat oven to 350 degrees FHeat oil in a large (8-8 qt) oven-proof dutch oven over medium-high heat. Add the beef and brown well on all sides. You may have to do this in batches and some extra oil may be necessary.While the last batch of meat is browning, place the flour in a medium bowl and whisk in the wine gradually so that no lumps form; set aside.Add the browned meat back to the dutch oven. Whisk the wine mixture again so it’s well combined, then add it to the meat. Stir until it begins to thicken. Then, stir in the beef stock. Stir in the brown sugar (if using), the bay leaves and the thyme.Add salt and pepper to taste. Stir in the carrots, potatoes and pearl onions.Cover and bake for 2-2½ hours, or until meat is tender. Add the mushrooms and bake for an additional 30 minutes.