Place chuck roast, Italian dressing seasoning, pepperoncini peppers (with juice), giardiniera, and beef broth into a slow cooker.
Cover with lid and cook on low for 8 hours or high for 4 hours.
Shred beef with a fork, then cook on low for 1 more hour.
Remove shredded beef and place on Martin’s Hoagie Rolls.
Top each sandwich with 2 slices provolone, and extra pepperoncini and giardiniera, if desired.