I modified a recipe I saw on A year of slow cooking, this recipe was beyond simple. I served the sandwich with au jus from a jar.
2 pounds beef chuck roast (thawed)
1 (16-ounce) jar peperoncini peppers
1 small yellow onion (chopped)
1 tablespoon of garlic powder
Place beef followed by the other 3 ingredients in crock pot. Cook on high for 5 hours. Drain mixture. Place on a toasted roll with pepper jack. Serve with au jus.
(after being drained, back in the crock pot)