01 -
Heat a skillet over medium-high heat with a little oil. Brown the beef roast on both sides without cooking through completely, about 3 minutes per side.
02 -
In a bowl, stir together beef broth, onion soup mix, au jus mix, and water until thoroughly combined.
03 -
Place the browned beef in the slow cooker. Pour the combined liquid mixture over the beef. Cover and cook on low for 8 hours without lifting the lid.
04 -
One hour before serving, shred the beef using two forks or slice thinly. Return the meat to the slow cooker and cook for an additional hour to reheat.
05 -
Place sub rolls on a baking sheet. Top each roll with shredded beef and add cheese slices on top. Broil in the oven or toaster oven for 1 to 2 minutes until cheese melts and rolls are lightly toasted.
06 -
Serve sandwiches warm with au jus sauce from the slow cooker. Strain and add extra beef broth if needed to thin the au jus.