Pre-heat oven to 400F (200C).
Heat a cast-iron skillet on medium heat (3-5 minutes). Rub the steak with oil and season all sides liberally with salt and pepper; place on heated skillet. Sear both sides for 2 minutes per side.
Transfer the steak to the oven immediately. After 10 minutes insert a thermometer into the thickest side of the steak. For a medium rare steak, pull steak out at 120F(50C). For medium-well done steak, remove from heat at 140F(60C).
Once out of the oven, let steak sit for a few minutes, slice and serve.