Optional sear (Flavor booster): Pat the chuck roast completely dry with paper towels and season with cracked black pepper. Heat olive oil in a large heavy skillet over high heat. Sear the beef for 3 to 4 minutes per side until a deep, dark golden-brown crust forms. (This step caramelizes the meat for richer pan gravy, but you can also place it raw directly into the slow cooker for true dump-and-go convenience).

Place in slow cooker: Transfer the seared chuck roast into the bottom of a 6-quart oval slow cooker insert.

Add seasonings: Sprinkle the dry ranch seasoning mix and the au jus gravy mix evenly across the top of the beef roast.

Top with butter and peppers: Place the stick of unsalted butter pats directly on top of the seasoned roast. Scatter 8 to 10 whole pepperoncini peppers around and on top of the beef. Pour 3 tablespoons of pepperoncini brine around the sides of the roast (do NOT add water or broth; the roast and butter will release ample rich savory juices).

Slow cook on LOW: Cover with the lid and cook on LOW for 8 hours (or on HIGH for 5 to 6 hours) until the beef is fork-tender and pulls apart effortlessly with zero resistance.

Shred and rest: Using two forks, shred the succulent beef directly in the slow cooker insert, letting it soak up all the glistening buttery au jus juices and braised peppers. Let rest in the warm juices for 10 minutes.

Garnish and serve: Ladle generous mounds of tender beef and savory pepperoncini gravy over creamy mashed potatoes, buttered egg noodles, or warm crusty sandwich hoagie rolls. Garnish with chopped fresh parsley and serve hot!