1. Rub the rib roast with Herbes de Provence, black pepper and kosher salt. Let sit uncovered overnight in the refrigerator.
2. The next day, pat dry and rub with butter.
3. Preheat 375ºF.
4. Bake for 10 minutes. Turn down oven temperature to 250ºF and until internal temperature reaches 120ºF, about 90 minutes. Remove from oven and tent with foil.
5. Let rest for 30 minutes before carving.