01 - Arrange sliced onion and minced garlic evenly across the bottom of the slow cooker insert.
02 - Rub chuck roast thoroughly with salt, pepper, thyme, and rosemary on all sides. Place seasoned roast directly on top of the onion bed.
03 - Pour beef broth, soy sauce, and Worcestershire sauce evenly over the roast and onions.
04 - Cover and cook on low setting for 8 hours until beef reaches fork-tender consistency and shreds easily.
05 - Transfer cooked beef to a cutting board. Shred using two forks, pulling apart with the grain. Return shredded meat to the slow cooker and stir well to absorb the au jus.
06 - Set oven to broil. Slice hoagie rolls in half lengthwise. Pile shredded beef generously onto the bottom halves and top with cheese slices if using.
07 - Arrange assembled sandwiches on a baking sheet. Broil for 2-3 minutes until cheese is bubbly and beginning to brown, watching closely to prevent burning.
08 - Transfer sandwiches to plates. Ladle remaining au jus from the slow cooker into small dipping bowls and serve alongside.