01 - Arrange sliced onions and minced garlic evenly across the bottom of the slow cooker insert.
02 - Rub the chuck roast thoroughly with salt, pepper, dried thyme, and dried rosemary. Place the seasoned beef directly on top of the onion bed.
03 - Pour beef broth, soy sauce, and Worcestershire sauce over the roast and onions. Ensure the liquid partially covers the meat.
04 - Cover and cook on low heat for 8 hours until the beef is fork-tender and easily shreds.
05 - Transfer the cooked beef to a cutting board. Using two forks, shred the meat into bite-sized pieces. Return the shredded beef to the slow cooker and toss gently to coat in the au jus.
06 - Set oven to broil. Split the hoagie rolls open and fill each with an even portion of shredded beef. Top with provolone or Swiss cheese if using.
07 - Arrange filled sandwiches on a baking sheet. Broil for 2–3 minutes until the cheese is melted and bubbly, watching closely to prevent burning.
08 - Transfer sandwiches to serving plates. Ladle the cooking liquid from the slow cooker into small bowls and serve alongside for dipping.