01 - Arrange sliced onion and minced garlic evenly in the bottom of the slow cooker insert.
02 - Rub the chuck roast thoroughly with salt, pepper, thyme, and rosemary. Place the seasoned meat directly on top of the onion layer.
03 - Pour beef broth, soy sauce, and Worcestershire sauce over the roast and vegetables.
04 - Cover and cook on low heat for 8 hours, or 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 in the au jus.
06 - Preheat the oven broiler. Split the hoagie rolls open and fill generously with the shredded beef. Top each sandwich with a slice of cheese if using.
07 - Arrange sandwiches on a baking sheet and broil for 2-3 minutes, watching closely, until the cheese is melted and bubbly.
08 - Serve immediately alongside small bowls of warm au jus from the slow cooker for dipping.