Preheat your oven to 250 degrees F or prepare your grill and let it settle at around that temperature.
Cook the steak until it reaches a temperature 10 degrees below the desired level of doneness, checking often with a meat thermometer
Move the steak to a plate and heat the cast iron pan on a stovetop. Add the neutral oil. When a drop of water shimmers on the oil, add the steak.
Flip it so all of the sides are seared for about 45 seconds to 1 minute each. Add the butter when removing the cast iron pan from the heat and flip the steak to coat it
Let the steak rest for 10 minutes and enjoy!