01 - Pat the beef chuck 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 beef for 3 to 4 minutes per side until a rich brown crust forms. Transfer meat to the slow cooker.
03 - Place potatoes, carrots, and sliced onion evenly around the beef in the slow cooker.
04 - Whisk together beef broth, tomato paste, Worcestershire sauce, minced garlic, dried thyme, and dried rosemary in a small bowl. Pour this mixture over the beef and vegetables. Add bay leaves.
05 - Cover and cook on low heat for 8 hours or until beef is fork-tender and vegetables are soft.
06 - Discard bay leaves. Transfer the beef to a cutting board and shred or slice to preferred thickness.
07 - For a thicker sauce, combine cornstarch and cold water in a small bowl and stir into the slow cooker. Cover and cook on high for an additional 10 to 15 minutes until sauce thickens.
08 - Plate beef alongside carrots and potatoes, spooning sauce over the top for a hearty presentation.