01 - Arrange the sliced onion and minced garlic evenly across the bottom of the slow cooker insert.
02 - Rub the chuck roast thoroughly with salt, black pepper, thyme, and rosemary. Place the seasoned roast directly on top of the onion bed.
03 - Pour the beef broth, soy sauce, and Worcestershire sauce over the roast and onions, ensuring the meat is partially submerged.
04 - Cover with the lid and cook on low heat for 8 hours. The beef is ready when it shreds effortlessly with a fork.
05 - Transfer the cooked beef to a cutting board. Using two forks, shred the meat into strands. Return the shredded beef to the slow cooker and mix well to absorb the au jus.
06 - Set your oven to broil. Slice the hoagie rolls open and heap the shredded beef onto the bottom halves. Top each sandwich with a slice of provolone or Swiss cheese.
07 - Arrange the assembled sandwiches on a baking sheet. Broil for 2 to 3 minutes, watching closely, until the cheese is bubbly and beginning to brown.
08 - Ladle the remaining cooking liquid from the slow cooker into small individual bowls. Serve the sandwiches alongside the au jus for dipping.