In a skillet, heat the oil and butter over medium-high heat.
Season the beef cubes with salt and pepper.
Sear the meat in small batches until nicely browned on all sides.
Once cooked, reserve in a Dutch oven.
Remove the excess fat and place the skillet back on the heat.
Deglaze with white wine.
With a fork, scrape the browned bits from the bottom and pour into the Dutch oven.
Add the beef stock, bay leaves and thyme.
Cover and simmer for 1 hour and 30 minutes.
Meanwhile, in a large skillet, heat the olive oil over medium-high heat. Brown the onion and bell pepper, stirring frequently, for about 15 minutes until soft. (If you can't add all the vegetables at once, add as much as you can. After a few minutes they'll have reduced and you'll be able to add the rest).
Add the garlic and cook for another minute, stirring constantly.
Add the tomatoes.
Simmer uncovered for about 30 minutes.
Once the beef has cooked, add the tomato mixture to the casserole.
Cover and simmer for another 45 minutes until the beef is very tender.
Add the olives 5 minutes before the end of the cooking time and adjust the seasoning.
Serve with herbed rice and broccoli.
Sofrito is sauce made from tomatoes, onions, peppers, garlic and fine herbs.