Prep the Beef: Pat beef dry and season with salt, pepper, and flour.
Brown the Meat: In a large Dutch oven, heat olive oil and butter over medium-high heat. Sear beef in batches until browned on all sides. Remove and set aside.
Sauté Aromatics: In the same pot, add onion and garlic. Cook until softened.
Add Tomato Paste: Stir in tomato paste and cook for 2 minutes to caramelize.
Deglaze: Add beef broth and Worcestershire sauce. Scrape up brown bits.
Combine Ingredients: Return beef to pot. Add carrots, potatoes, celery, bay leaves, and thyme.
Simmer: Cover and simmer on low for 2.5–3 hours, or transfer to a 300°F oven.
Thicken (Optional): Mix cornstarch and water. Stir into stew 15 minutes before serving.
Rest: Let stew rest 10 minutes. Remove bay leaves, taste, and adjust seasoning.