When you cook prime rib, you may end up with leftovers. Freezing the prime rib preserves the flavor and allows you to enjoy the beef at a later date. Since the prime rib leftovers are already cooked, they only need to be reheated to a safe internal temperature. Reheating the prime rib safely and properly keeps the meat juicy.
Thaw frozen prime rib in the refrigerator overnight.
Wrap the thawed prime rib in aluminum foil. The foil will keep the meat from drying out completely.
Heat the oven to 250 degrees F. Place the foil-wrapped prime rib on a cookie sheet.
Heat the prime rib until it reaches an internal temperature of 165 degrees F. Test temperature with a meat thermometer.