Place the beef chuck roast, au jus gravy mix, beef consommé, beef broth, and sliced onion into a 6-quart slow cooker. Make sure the roast is fully covered by the liquid for even cooking.

Cover the slow cooker with its lid and cook everything on low heat for 8 hours. The beef will become fork-tender and soak up all the rich flavors.

After cooking, carefully remove the beef from the slow cooker, shred it into bite-sized pieces using two forks, and return it to the slow cooker to soak up the juices.

Preheat your oven’s broiler. Pile the shredded beef onto hoagie rolls and top each sandwich with provolone cheese. Place the sandwiches on a baking sheet and broil for about 2 minutes, or until the cheese has melted.

Serve the sandwiches hot with a small cup of the hot cooking juices on the side for dipping.

Place leftover beef with its juices in an airtight container in the refrigerator for up to 4 days.

For longer storage, freeze the shredded beef and cooking liquid for up to 3 months.

To reheat, warm in a saucepan over low heat or microwave at 50% power in 1-2 minute increments.