01 - Pat the beef roast dry with paper towels. Season all sides generously with salt, pepper, dried thyme, and dried rosemary, pressing the spices into the meat to adhere.
02 - Heat a large skillet over medium-high heat. Sear the seasoned roast on all sides until deeply browned, approximately 3-4 minutes per side. This step develops flavor but is optional.
03 - Arrange the baby potatoes, carrot pieces, chopped celery, and onion wedges in an even layer at the bottom of the slow cooker insert.
04 - Place the seared beef roast directly on top of the vegetable bed. Sprinkle the minced garlic evenly over the roast and tuck the bay leaves around the meat.
05 - Pour the beef broth and Worcestershire sauce evenly over the roast and vegetables. Avoid submerging the roast completely—liquid should come about halfway up the meat.
06 - Cover with the lid and cook on low setting for 8 hours. The beef is done when it forks apart easily and vegetables are tender.
07 - Carefully transfer the roast and vegetables to a warm serving platter using tongs. Tent loosely with foil to keep warm while preparing gravy.
08 - For thicker gravy, whisk cornstarch with cold water until smooth. Stir the slurry into the hot cooking liquid, set slow cooker to high, and cook for 10-15 minutes until thickened, stirring occasionally.
09 - Slice or shred the beef against the grain. Serve portions of meat with vegetables alongside, ladled with gravy. Garnish generously with chopped fresh parsley.