📋 Instructions

1. 1Layer the aromatics — Scatter the sliced onion and smashed garlic across the bottom of a 6-quart slow cooker. This bed keeps the roast off the hot ceramic floor and flavors the juices from below.
2. 2Season the roast — Pat the chuck roast dry with paper towels and set it on top of the onions. Sprinkle the ranch packet, au jus packet, and black pepper evenly over every surface.
3. 3Add butter and peppers — Place the whole stick of butter on top of the roast, then tuck the pepperoncini around the sides and pour the 1/4 cup brine and 1/2 cup beef broth into the bottom of the pot.
4. 4Slow cook on low — Cover and cook on LOW for 7 to 8 hours (or HIGH for 4 to 5 hours) until the beef shreds easily with a fork and reaches 200 to 205 F (93 to 96 C) at the center. You will see bubbling edges and the meat should offer no resistance when you twist a fork in it.
5. 5Rest before shredding — Turn the cooker off and let the roast rest, covered, for 15 minutes. This lets the juices redistribute so the meat stays moist instead of drying out as you pull it apart.
6. 6Shred into the sauce — Use two forks to pull the beef apart right in the pot, discarding any large lumps of fat. Stir the shreds through the buttery pepperoncini juices until evenly coated.
7. 7Thicken the gravy — If you want a thicker gravy, set the cooker to HIGH, whisk the cornstarch slurry into the juices, and simmer uncovered for 10 to 15 minutes until it coats the back of a spoon.
8. 8Taste and serve — Taste the gravy and add pepper or a splash more brine if it needs lift. Pile the beef over mashed potatoes, rice, or toasted buns and spoon the gravy on top.