In a small bowl, stir together the salt, pepper, garlic powder, and onion salt.
Sprinkle the seasoning blend evenly over all sides of the chuck roast.
Place the seasoned roast into the bowl of your slow cooker.
Pour in the beef broth, beef consommé, beer, Worcestershire sauce, and toss in the garlic cloves.
Cover and cook on low for 8 hours, or until the meat is fall-apart tender.
Once cooked, carefully remove the meat and strain the remaining liquid into a bowl or container. This is your dipping au jus—don’t toss it!
Use two forks to shred the beef into bite-sized pieces. Cover with foil to keep warm.
Slice your sandwich rolls in half, spread with butter, and place under the broiler for 1-2 minutes until golden and slightly crisp.
Pile shredded beef onto each roll and serve with a side of the warm au jus for dipping.