01 - Preheat oven to 320°F.
02 - Pat beef cubes dry with paper towels. Season with salt and pepper, then toss with flour to coat lightly.
03 - Heat olive oil and butter in a large Dutch oven or oven-safe casserole dish over medium-high heat. Brown beef in batches until seared on all sides. Transfer to a plate.
04 - In the same dish, add onions, carrots, and celery. Sauté for 5 minutes until softened. Add garlic and cook for 1 additional minute.
05 - Stir in tomato paste and cook for 1 minute. Pour in red wine if using, scraping the bottom to deglaze. Let simmer for 2 minutes.
06 - Return beef to the pot. Add potatoes, chopped tomatoes, beef stock, thyme, and bay leaves. Mix thoroughly.
07 - Bring to a simmer, cover with lid, and transfer to oven. Cook for 2 hours, stirring halfway through, until beef is tender.
08 - Remove bay leaves. Adjust seasoning with salt and pepper as needed.
09 - Serve hot, optionally garnished with chopped parsley.