Pat the beef chuck roast completely dry with paper towels. Season generously all over with coarse salt and cracked black pepper.

Heat 2 tablespoons olive oil in a heavy cast iron skillet over high heat. Sear the roast for 3-4 minutes per side until a deep, dark golden-brown caramelized crust forms on all sides. Transfer the seared roast directly into the slow cooker basin.

Scatter baby carrots, halved baby potatoes, and smashed garlic cloves around and under the sides of the roast.

Sprinkle the ranch seasoning mix and au jus gravy mix evenly across the top of the seared beef.

Place the sliced pats of butter on top of the seasoned roast. Arrange the whole pepperoncini peppers on and around the meat, then pour in the pepperoncini pickling juice and beef bone broth around the perimeter (not washing off the top seasonings).

Cover with the slow cooker lid and cook on LOW for 8 to 9 hours (or HIGH for 5 to 6 hours) until the beef is meltingly tender and easily pulls apart with a fork.

Use two large forks to shred the roast into thick, succulent chunks directly in the slow cooker, allowing the juicy meat fibers to soak up the rich, buttery, savory pepperoncini gravy.

Garnish with fresh thyme and rosemary. Serve hot spooned over garlic mashed potatoes, buttered egg noodles, or stuffed inside toasted brioche buns with melted provolone.