HEAT WATER IN SOUS VIDE MACHINE/OVEN: Fill the sous vide container about ¾ full with water. For medium rare cook, set the temperature to 132-134F/132-134F/55-56.7C . For medium cook, set to 140F/60C. The water will take about 15 minutes to reach the correct temperature (or less if you start with warm water and a smaller container).

SEASON MEAT: Generously sprinkle the roast with kosher salt, black pepper, thyme, dried rosemary and garlic powder on all sides. Feel free to use a sprig or two fresh herbs, but don't overdo the rosemary - it's quite powerful.

PREPARE MEAT FOR SOUS VIDE: If using a vacuum sealer, fold over a flap on one 1-quart vacuum seal bag. Place meat inside the bag and unfold the flap. Seal the bag (and vacuum out the air) as per machine instructions. (Note 1 for displacement method with ziploc bag).

SOUS VIDE MEAT: Plunge the bag into the pre-heated sous vide bath. It will sink to the bottom (or use water displacement method). Sous vide prime rib for 3 ½ hours or maximum 6 hours if meat is 2-3 inches/5-7.6 cm. If meat is lesser quality e.g. choice or select, sous vide for 6-8 hours (the lower the quality, the longer the cook time needed). Note 2

SEAR OUTSIDE OF BEEF TO FINISH ROAST: Remove meat from sealed bag, reserving the juices accumulated in the bag for gravy if desired. Pat dry well with paper towels. Rub oil over meat and sprinkle again with kosher salt, pepper and garlic powder. Let rest for 10 minutes while you prepare your skillet (cast iron is best but any skillet will do). Heat skillet to high (9/10) with a teaspoon of oil. Open windows for smoke clearance. Sear beef about 1 minute on each side (including the edges) to achieve a deep brown color - maillard reaction. Remove from skillet and keep warm while you prepare a quick gravy if desired, Note 3. Slice the beef and serve with horseradish, horseradish cream or gravy. Sprinkle lightly with finishing sea salt if desired.