Preheat oven to 350f. Using a paring knife, make small slits into roast about 3 inches apart and press the garlic slivers into the slits. Using a pastry brush, coat the entire roast with the mustard. Sprinkle marinade to completely cover the roast. Place on a rack in a roasting and cook until a meat thermometer inserted in center reads 130f. Remove from oven, cover with foil, and allow to rest for 10 to 15 minutes.
to make au jus, place roasting pan over stovetop burners on med-low. whisk in wine and scrape the little brown bits from the bottom of the roasting pan. reduce slightly and add broth. Bring to a simmer and reduce slightly. serve along with slices prime rib.