01 - Pat the beef roast dry and season all sides evenly with kosher salt and black pepper.
02 - Heat olive oil in a large skillet over medium-high heat. Sear the roast on all sides for 3 to 4 minutes per side until browned.
03 - Place carrots, potatoes, celery, onion, and minced garlic at the bottom of the slow cooker.
04 - Lay the seared roast directly on top of the arranged vegetables.
05 - Whisk together beef broth, Worcestershire sauce, tomato paste, dried thyme, dried rosemary, and bay leaves in a bowl; pour evenly over the roast and vegetables.
06 - Cover and cook on Low for 8 hours, until beef is fork-tender and vegetables are cooked through.
07 - Transfer the roast and vegetables to a serving platter and tent with foil to keep warm.
08 - Discard bay leaves and skim any excess fat from the cooking liquid remaining in the slow cooker.
09 - In a small bowl, combine cornstarch (or flour) with cold water to form a smooth mixture.
10 - Stir the slurry into the cooking liquid, turn slow cooker to High, and cook uncovered for 10 to 15 minutes until gravy thickens.
11 - Slice or shred the beef and serve alongside vegetables topped with the prepared gravy.