01 -
Heat a small amount of oil in a skillet over medium-high heat. Brown the chuck roast on all sides until a rich crust forms, about 4 minutes per side, without cooking through.
02 -
In a medium bowl, combine beef broth, onion soup mix, au jus gravy mix, and water. Stir to blend evenly.
03 -
Place the browned roast in the slow cooker. Pour the broth mixture over the beef. Cover and cook on low for 8 hours without lifting the lid.
04 -
One hour before serving, shred the beef with two forks or slice thinly. Return the meat to the slow cooker and continue cooking on low for another hour.
05 -
Preheat broiler. Place sub rolls on a baking sheet, top each with shredded beef, and layer on provolone slices. Broil for 2 to 3 minutes until cheese melts and rolls are lightly toasted, watching closely.
06 -
Strain the cooking liquid to serve as au jus on the side. Add additional beef broth if needed to ensure sufficient dipping sauce.