01 - Sprinkle salt and pepper evenly over the entire beef roast.
02 - Heat a large skillet over medium-high heat and brown the roast on all sides for 2 to 3 minutes each to develop flavor; this step is optional.
03 - Place carrots, celery, onion, garlic, and halved potatoes at the bottom of the slow cooker.
04 - Position the seared beef roast atop the arranged vegetables in the slow cooker.
05 - Combine beef broth, tomato paste, Worcestershire sauce, and Dijon mustard in a small bowl; whisk until smooth and pour over the roast.
06 - Nestle rosemary, thyme, and bay leaves around the meat for flavor infusion.
07 - Cover and cook on low setting for 8 hours or high setting for 4 to 5 hours until the beef is tender and vegetables are fully cooked.
08 - Transfer roast and vegetables to a serving platter, discarding herb stems and bay leaves.
09 - Pour cooking liquid into a saucepan, stir in cornstarch slurry, and simmer for 2 to 3 minutes until thickened.
10 - Slice or shred the beef and serve alongside the cooked vegetables and prepared gravy.