01 - Pat the chuck roast dry with paper towels and season all sides generously with kosher salt and black pepper.
02 - Heat a large skillet over medium-high heat. Sear the roast on all sides until deeply browned, approximately 4 minutes per side. Transfer the seared beef to the slow cooker.
03 - Place carrots, potatoes, celery, and onion around and beneath the beef in the slow cooker insert.
04 - Scatter minced garlic, thyme, rosemary, and bay leaves over the meat and vegetables.
05 - Whisk together beef broth, Worcestershire sauce, and tomato paste if using. Pour the mixture evenly over the roast and vegetables.
06 - Cover and cook on LOW setting for 8 hours, or until the beef pulls apart easily with a fork and vegetables are completely tender.
07 - Transfer the roast and vegetables to a serving platter. Discard the bay leaves and herb stems.
08 - For a thicker consistency, whisk cornstarch with 2 tbsp cold water until smooth. Stir into the cooking liquid in the slow cooker and cook on HIGH for 5 minutes until thickened.
09 - Serve the beef sliced or shredded, accompanied by vegetables and gravy.