To a large slow cooker add the water. Place the chuck roast in the water then sprinkle the dry ranch seasoning and dry au juice seasoning over the roast. Add the pepperoncini to the slow cooker.
Lastly, place the butter slices over the meat.
Cover and cook on low for 8-9 hours.
Remove lid and shred the meat. Serve over mashed potatoes if desired.
Notes
Store leftovers in an airtight container in the fridge for 4-5 days. Do not add extra salt -- there is salt in the seasoning packets you'll use that will be enough for the meat. Do not cook on high. Cook on low — this will give you the best results.