01 - Layer the sliced onions and minced garlic evenly across the bottom of the slow cooker insert.
02 - Rub the chuck roast thoroughly with salt, black pepper, dried thyme, and dried rosemary on all sides. Place the seasoned roast directly on top of the onion bed.
03 - Pour the beef broth, soy sauce, and Worcestershire sauce evenly over the roast and onions.
04 - Cover and cook on low heat for 8 hours until the beef shreds easily with a fork.
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 well to coat with the accumulated juices.
06 - Set the oven to broil. Slice the hoagie rolls lengthwise and fill each with the shredded beef mixture. Top with cheese slices if using.
07 - Arrange the filled rolls on a baking sheet. Broil for 2 to 3 minutes until the cheese melts and the bread edges are lightly toasted. Serve immediately alongside small bowls of the au jus from the slow cooker for dipping.