01 - Arrange sliced onions 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 onion layer.
03 - Pour beef broth, soy sauce, and Worcestershire sauce over the beef and onions.
04 - Cover and cook on low setting for 8 hours until beef is fork-tender and easily shreds.
05 - Transfer cooked beef to a cutting board. Using two forks, shred meat into strands. Return shredded beef to crockpot and stir well to absorb au jus.
06 - Set oven to broil. Split hoagie rolls open and pile shredded beef onto bottom halves. Top with cheese slice if using.
07 - Arrange assembled sandwiches on baking sheet. Broil for 2-3 minutes until cheese is melted and bubbly.
08 - Transfer sandwiches to plates. Ladle reserved au jus from crockpot into small dipping bowls. Serve immediately.