Preheat the oven to 450°F (230°C). Take the prime rib roast out of the refrigerator and let it sit at room temperature for about 1 hour before cooking.

In a small bowl, mix together the olive oil, minced garlic, rosemary, thyme, salt, black pepper, and onion powder to create a paste.

Rub the paste all over the prime rib roast, ensuring it is evenly coated on all sides.

Place the roast on a rack in a roasting pan with the fat side up. Insert a meat thermometer into the thickest part of the roast.

Roast in the preheated oven for 15 minutes to sear the outside. Then, reduce the oven temperature to 325°F (165°C) and continue roasting until the internal temperature reaches 120°F (49°C) for medium-rare, about 1 hour 45 minutes.

Remove the roast from the oven and let it rest for at least 20 minutes before carving. This allows the juices to redistribute.

Slice the prime rib roast against the grain into thick pieces and serve immediately.