Let the steak rest at room temperature for 30 minutes.
Preheat oven to 425. Heat a cast-iron skillet over high heat until very hot.
Season the steak heavily with salt and pepper on all sides. Add the oil to the skillet, then place the steak in the skillet and do not move it. Cook until a nice sear forms, about 1 minute each side. Remove the skillet from the heat, transfer the steak to the oven.
Cook 5 minutes for medium rare, 6 to 7 minutes for medium. Transfer to a serving plate and pour the pan drippings over the steak.along with some butter. Let stand for 2 minutes before serving or cutting.