Preheat your oven to 450°F.
Combine the coffee in a bowl with the vanilla seeds, sea salt and black pepper.
⅓ cup coffee grounds, ¼ vanilla bean, 2 tablespoon sea salt, 1 tablespoon freshly ground black pepper
Place the roast in a roasting pan, fat side up, and rub the vanilla and coffee mixture over the roast, mainly on the fatty part.
12 lb bone-in prime rib roast
Now let the roast stand for 30 minutes at room temperature before roasting.
Place in the oven to roast for 15 minutes before reducing the temperature to 325°F. For a medium rare roast, cook for another 2 ½ hours, or unti the temperature at the center of the roast reaches 125°F.
When cooked, remove the roast from the oven and set aside to cool for at least 20 minutes.
Scrape off the excess coffee rub, carve and serve with a simple side salad or vegetables.