01 - Pat the chuck roast completely dry with paper towels and season all sides generously with salt and black pepper.
02 - Heat a large skillet over medium-high heat. Sear the roast on all sides until deeply browned, about 2 to 3 minutes per side.
03 - Arrange carrots, potatoes, celery, onion, and garlic in an even layer at the bottom of the slow cooker.
04 - Place the seared roast on top of the vegetable bed.
05 - Whisk together beef broth, red wine, tomato paste, Worcestershire sauce, thyme, and rosemary in a bowl until well combined.
06 - Pour the liquid mixture over the roast and vegetables. Tuck bay leaves into the liquid.
07 - Cover and cook on LOW for 8 hours or until the meat pulls apart easily with a fork.
08 - Remove the roast and vegetables to a serving platter. Discard bay leaves.
09 - Whisk cornstarch and cold water until smooth. Stir into the cooking liquid, turn to HIGH, and cook for 10 to 15 minutes until thickened.
10 - Slice or shred the beef and serve with vegetables, drizzled with thickened sauce.