Fill your sous vide container or pot with water and turn the machine on according to manufactures instructions to 130° F or 54.4° C for medium-rare, or to the desired finished temperature.
Season the steak liberally on all sides with kosher salt and freshly ground pepper.
Place a thyme sprig on each side of the steak, then place it in a vacuum seal bag or ziplock bag.
Vacuum seal the bag if using a vacuum sealer, or if using a ziplock bag; partially seal it removing as much air as possible, then use the water displacement method by placing the bag in the water (always keeping the opening above the water line) to push the rest of the air out before sealing it.
Clip the sealed bag to the side of the container to keep it submerged and cook between 1 and 3 hours.
Remove the bag from the water bath and let the steak rest in the bag for 10 to 15 minutes.
Cut the bag open and place the steak on a paper towel-lined plate and pat as dry as possible (keep the juices for a quick pan sauce if you prefer).
To sear the steak in a skillet
Heat a cast iron skillet over high heat until it just starts to smoke. Drizzle enough canola oil to coat the bottom of the pan and let that heat up for a few seconds.
Place the steak in the skillet and sear for about 30 to 45 seconds on each side until golden brown. Going longer than 1 minute on each side will cause the steak to cook more than desired.
As soon as the steak hits the skillet, add a few tablespoons of butter along with the thyme sprigs. Once the butter melts, begin basting it over the steak with the thyme until it’s finished the sear is finished.
Slice and serve immediately. No need to rest it.
Recipe makes 1 steak, but can easily be scaled up for more.
New York strip steak was used in this post, but recipe works for any cut.
If the steak isn’t staying submerged, you can put bowl or plate on top of it to keep it down.