Place the chuck roast in the bottom of a roasting pan. Sprinkle both sides with au jus mix.
When it is done, place it in a slow cooker. Place butter on top of the roast, pepperoncini peppers, and sprinkle ranch dressing mix over it.
Cover the slow cooker, being careful to seal it tightly around the edges of the pan.
Cook it for approximately 8 hours or until tenderized. Once cooked, let sit for 10 minutes. Then place it cutting board & shred the meat gently using forks.
Place it again in the slow cooker. Add flour and stir until it’s completely mixed in with the juices. Simmer for a few minutes until desired consistency is reached. Serve over roast.