01 -
Heat a skillet over medium-high heat with a small amount of oil. Brown the chuck roast on all sides without cooking through to develop flavor.
02 -
Place the browned chuck roast in the slow cooker. In a bowl, combine beef broth, onion soup mix, au jus gravy mix, and water; stir well.
03 -
Pour the broth mixture over the roast in the slow cooker. Cover and cook on low for 8 hours without lifting the lid to maintain tenderness.
04 -
One hour before serving, shred the beef with two forks or slice it thinly. Return the shredded meat to the slow cooker and continue cooking for 1 hour.
05 -
Preheat the broiler. On a baking sheet, place sub rolls and top each with shredded beef and a slice of cheese.
06 -
Broil sandwiches for 1 to 2 minutes, until the cheese melts and rolls are lightly toasted. Watch carefully to avoid burning.
07 -
Serve sandwiches warm with au jus from the slow cooker. Strain au jus if desired and add extra beef broth to increase quantity if needed.