Place chuck roast in slow cooker. Sprinkle ranch seasoning and au jus mix over the meat. Add butter, pepperoncini peppers, and pepperoncini juice. Cover and cook on low for 8 hours or high for 5 hours until tender. Shred beef in the juices. Serve on rolls with extra juices spooned on top.
Notes
Do not add extra liquid. Toast rolls lightly for better texture.