Preheat oven to 350 for ten minutes.
Heat cast iron pan on stovetop to smoking point.
Pre-salt each side of steak a few minutes in advance.
Put steak into pan and sear each side for approximately two minutes.
Put steak and pan into oven.
Cook for 4-8 minutes until steak reaches internal temperature of 120.
Take out of oven and allow to rest for five minutes.