Set the sous vide cooker. Preheat water temperature to 55C/131F for medium rare, 60C/140F for medium, 65C/149F for medium well, 70C/158F or above for well done
Use butchers twine to truss the rib eye into even sections. This helps to retain a nice shape after sous vide
Season the beef with some salt, pepper and olive oil before searing the beef
Sear all sides of the beef in a hot pan, baste with butter, until the beef has a nice, dark caramelization all over the exterior. Remember its a quick sear, dont cook it through
Add rosemary and the garlic into the pan, baste with the hot butter quickly, remove it as soon as the rosemary is still bright green and when the garlic is not burnt yet
Rest the rib eye in room temperature until slightly cool. Transfer the rib eye to a zip bloc bag or sous vide bag, add together the cooking juices and herbs, set the bag into the preheated water
Sous vide for around 2 hours. (You can ensure the doneness by checking the internal meat temperature by using a meat thermometer)
Just before you serve the rib eye, remove the beef from the bag, dry it with kitchen paper. Put the beef into the hot pan again with butter for a final sear
Rest for 5-10 minutes, dont forget to remove the butchers twine, cut into slices and serve with your favorite vegetables, enjoy
