Season the beef chuck roast with salt and pepper on all sides.
Place the roast in the slow cooker.
Sprinkle the ranch dressing mix over the roast.
Sprinkle the au jus gravy mix on top of the ranch seasoning.
Place the pepperoncini peppers around the roast.
Cut the butter into slices and place on top of the roast.
Cover the slow cooker with the lid.
Set the slow cooker to low and cook for 8 hours.
Once cooked, shred the beef using two forks.
Serve with the cooking juices over the top.