Place the roast into your slow cooker and evenly sprinkle both seasoning packets over top. Top with the butter and peperoncinis (about half of the jar plus 3-4 tbsp of the juice).
Cover and cook on LOW for approximately 8 hours or until the beef easily shreds with a fork.
Use a couple of forks to shred the beef and seperate and remove any excess fat.
If you're making sandwiches, preheat your oven to 400 degrees and place your hoagie rolls onto a large baking sheet and fill with the shredded beef. Top each one with a slice of provolone cheese and bake for about 2 minutes or until the cheese is melted and the bread is toasty.