01 - Pat the beef roast dry with paper towels. Season all sides generously with salt and pepper.
02 - In a large skillet over medium-high heat, heat olive oil. Sear the roast on all sides until deeply browned, about 4 minutes per side. Transfer to the slow cooker.
03 - Add carrots, parsnips, potatoes, onions, celery, and garlic to the slow cooker, arranging them around and beneath the beef.
04 - In a small bowl, whisk together beef broth, wine (if using), tomato paste, and Worcestershire sauce until smooth. Pour mixture evenly over the beef and vegetables.
05 - Sprinkle thyme, rosemary, and bay leaves over the contents of the slow cooker.
06 - Cover and cook on low for 8–9 hours or on high for 4–5 hours, until beef is fork-tender and vegetables are cooked through.
07 - Remove bay leaves and herb stems (if using fresh). Slice or shred the beef and serve with vegetables and pan juices.