Pat the prime rib dry. Mix kosher salt, black pepper, garlic powder, and onion powder. Season the roast generously on all sides. Place on a wire rack over a sheet pan, uncovered, in the refrigerator overnight (at least 12 hours). This is the trick — the dry brine transforms the crust.

Remove the roast from the fridge 2 hours before cooking to bring to room temperature.

Cut small slits in the meat and insert garlic slivers. Rub with olive oil and press fresh rosemary and thyme into the surface.

Preheat oven to 250°F. Place roast bone-side down in a roasting pan. Roast until internal temperature reaches 120°F for rare or 130°F for medium-rare (about 3-4 hours).

Remove roast and tent loosely with foil. Increase oven to 500°F. Return the roast and sear for 8-10 minutes until a deep brown crust forms.

Rest for at least 20 minutes before carving. Slice against the bone and serve with horseradish cream or au jus.