1. Heat olive oil in a large pot over medium-high heat. Season beef with salt and pepper and sear until browned on all sides. Remove and set aside.
2. In the same pot, sauté onion, celery, and garlic until softened, about 5 minutes. Add tomato paste and cook for 1 minute.
3. Deglaze the pot with a small amount of beef broth, scraping up any browned bits. Return beef to the pot.
4. Add carrots, potatoes, remaining broth, Worcestershire sauce, bay leaf, and thyme. Stir to combine.
5. Bring to a boil, then reduce heat to low and simmer for 1½-2 hours, or until beef is tender and vegetables are soft. Remove bay leaf before serving.
6. Garnish with fresh parsley and serve warm.