Lightly grease the slow cooker insert. Place the chuck roast in the bottom.

In a bowl, whisk together beef consommé, French onion soup, beef broth, Worcestershire sauce, soy sauce, garlic powder, and black pepper. Pour over the roast.

Cover and cook on LOW for 8 hours (or HIGH for 4-5 hours), until the meat is very tender.

Remove the roast to a cutting board and shred the beef using two forks. Discard large pieces of fat.

Strain the liquid remaining in the slow cooker through a fine mesh sieve into a bowl to create a smooth au jus. Return the shredded meat to the slow cooker and ladle a small amount of au jus over it to keep it moist.

Preheat your oven's broiler. Split the hoagie rolls, lightly butter them if desired, and place cut-side up on a baking sheet. Broil for 1-2 minutes until toasted.

Remove rolls from the oven and pile generous amounts of warm shredded beef onto the bottom halves. Top with 2 slices of provolone cheese per sandwich.

Return to the broiler for 1-2 minutes until the cheese is melted and bubbly.

Pour the strained au jus into small cups for dipping. Serve sandwiches immediately with the au jus and a sprinkle of fresh parsley.