Preheat the oven to 160°C.
Heat a large cast iron casserole dish on a medium/high heat. Add the olive oil.
Brown the roast on all sides, remove from the dish and place to one side.
Add the onions, garlic, carrot, celery, bay leaves, and thyme.
Sauté for 5 minutes.
Add the bone broth and stir well, scraping the bottom of the dish with a wooden spoon.
Return the beef roast to the casserole dish.
Put the lid on the dish and place into the oven to cook for 4 hours.
When the beef is tender, remove from the casserole dish and place on a serving platter and keep warm.
