01 -
Heat a skillet with a small amount of oil over medium-high heat. Brown the chuck roast on all sides without cooking through, about 3 minutes per side. Remove and place into the slow cooker.
02 -
In a medium bowl, whisk together the beef broth, onion soup mix, au jus gravy mix, and water until fully combined.
03 -
Pour the broth mixture over the beef in the slow cooker. Cover and cook on low for 8 hours without lifting the lid to ensure tender meat.
04 -
About one hour before serving, shred the beef using two forks or thinly slice it. Return the shredded meat to the slow cooker and keep warm for the remaining time.
05 -
Preheat the broiler. Place sub rolls on a baking sheet, top with shredded beef, then layer with provolone slices. Broil for 2 to 3 minutes until cheese melts and rolls are lightly toasted. Watch carefully to avoid burning.
06 -
Serve sandwiches alongside strained au jus from the slow cooker. Optionally, add extra beef broth to the au jus for additional volume.