1Spray 3 1/2- to 4-quart slow cooker with cooking spray. Sprinkle beef with salt. In slow cooker, place beef (if roast comes in netting or is tied, do not remove) and onion. Mix remaining ingredients except rolls; pour over beef. Cover; cook on Low heat setting 7 to 8 hours.
2Skim fat from surface of juices; discard bay leaf and peppercorns. Remove beef and vegetables from slow cooker; place beef on cutting board (remove netting or strings). Cut beef into thin slices. Fill rolls with beef; top with onions and sprinkle with cheese. Serve with broth from cooker for dipping.