Preheat the oven to 450°F.
Place the rib roast, bone-side down, and fat-side up in a roasting pan that has been oiled. Season with salt and pepper.
Place your thermometer in the thickest part of the roast being careful not to touch any bone.
Sear the roast for 20 minutes in the hot oven. When done, remove from oven.
While the roast is searing, mix the butter, mustard, Worcestershire sauce, garlic, rosemary, pepper, and salt in a bowl.
When the roast is done searing, slather the butter paste over the sides and top of the roast.
Lower the oven temperature to 350°F. and return the roast to the oven.
Continue roasting until the thermometer reaches around 118°F. for medium rare.
Remove the roast from the oven, place on a cutting board, cover with aluminum foil and let rest for about 20 minutes or until the internal temperature rises up to 125°F.
Slice the rib roast, plate and serve.