Liberally sprinkle kosher salt all over each side of the steak, so that you can barely see any red. Crank on lots of freshly cracker black pepper as well.
Allow steak to sit at room temperature for 30 t0 45 minutes.
Rub and shake off all the excess salt and pepper.
Place into a vacuum sealed bag.
Set your sous vide to 138 for right in between medium rare and medium. You can set it to whatever temperature you want depending on how you like your steak.
Set the timer for 1 hour
Add your steaks. If they float then use a brick or heavy weight to keep the under the water.
When the timer goes off, remove the steak. Allow to cool for 5 minutes before removing from the bag.
Heat a cast iron pan over medium high heat. Coat with cooking oil.
Cook the steak, 1 minute per side or until browned, Flip and repeat.
Rest steak for 3-5 minutes before cutting into.