Place the chuck roast in the slow cooker.
Sprinkle the ranch seasoning mix and au jus gravy mix evenly over the roast.
Add the minced garlic, pepperoncini peppers, and butter on top.
Pour the beef broth and pepperoncini juice around the roast.
Cover and cook on LOW for 8–10 hours or HIGH for 4–5 hours, until the meat is fork-tender.
Remove the roast and shred or slice as desired.
Return the meat to the slow cooker and spoon some of the juices over the top.
Serve with mashed potatoes, rice, noodles, or roasted vegetables.