Prepare the Beef: Trim the beef if necessary and place it in the slow cooker. Add the drained giardiniera, about 3/4 of the pepperoncini, reserved pickling liquid, Italian salad dressing mix, and beef broth.

Slow Cook: Cover the slow cooker and cook on low for 8 to 10 hours or high for 5 hours.

Finish the Beef and Juices: Remove the beef to a plate or bowl and pour the liquids through a strainer into a saucepan. Bring the liquids to a boil; reduce the heat to low and simmer for 5 to 7 minutes or until slightly reduced and the flavors are concentrated; set aside. Shred the beef.

Toast the Hoagie Rolls: Split the rolls and brush the cut sides with olive oil. Place on a pan, cut side up, and broil for 1 to 2 minutes or until lightly toasted.

Make Sandwiches: Top the rolls with beef and some of the reserved pepperoncini. Drizzle with a little of the reserved liquids and top with provolone cheese. Broil for 1 minutes or just until the cheese has melted.