Heat the oven to 325°F and season the chuck roast with the salt and black pepper.
Heat the oil in a Dutch oven over medium-high heat and brown the roast for 4 minutes on each broad side.
Add the onion, broth, Worcestershire sauce and garlic, cover and braise for 2 1/2 to 3 hours until the beef reaches about 195°F and separates easily.
Rest the beef for 10 minutes, then shred it and discard any large seams of fat.
Strain the braising liquid into a saucepan, skim the fat and simmer the jus for 5 minutes; return the beef to enough jus to keep it moist and heat it to 165°F.
Split the rolls, butter the cut sides and toast them in a dry skillet until crisp at the edges.
Fill each roll with hot beef and ladle the remaining jus into 6 small bowls for dipping.