Season the beef chuck roast on all sides with the salt and black pepper.
Place the carrot chunks, potato chunks, and quartered onion in the bottom of the slow cooker.
Set the seasoned roast on top of the vegetables.
Add the smashed garlic, beef broth, Worcestershire sauce, rosemary sprigs, and bay leaves.
Cover and cook on low for 8 hours, until the beef pulls apart easily with a fork.
Remove the rosemary sprigs and bay leaves before serving.