Sprinkle the cubes of beef with the salt, pepper and flour, toss briefly to thoroughly coat the beef.Heat the oil and butter in a Dutch oven over medium-high heat. Once hot, add the beef, a few cubes at a time so as to not overcrowd. Brown the beef on all sides and transfer to a plate.Add the bell peppers, onions and garlic to the Dutch oven and cook for 5 minutes until softened, scraping up the browned bits from the bottom of the pan. Add the red wine and bring to a rapid boil for 2 minutes.Return the beef to the Dutch oven with the remaining ingredients. Bring the stew to a boil, reduce the heat to low and simmer, covered for 90 minutes until the beef is fork tender.This stew is even better the next day!