01 - Generously season the beef roast with kosher salt and black pepper on all sides.
02 - Place sliced onion, carrots, celery, and smashed garlic cloves in the base of the slow cooker.
03 - Set the beef roast atop the vegetables and evenly sprinkle dried thyme, rosemary, and add the bay leaf.
04 - Pour beef broth and Worcestershire sauce over the roast and vegetables in the slow cooker.
05 - Cover and cook on low heat for 8 hours, or until the beef is fork-tender and easily shreds.
06 - Transfer the roast and vegetables to a serving platter and tent loosely with foil to retain heat.
07 - Skim excess fat from the slow cooker juices remaining in the pot.
08 - Combine cornstarch or flour with water to form a smooth slurry, then stir into the juices.
09 - Set slow cooker to high heat and cook uncovered for 10–15 minutes until the gravy thickens to desired consistency.
10 - Slice or shred the beef and serve alongside the vegetables, spooning hot gravy over all.