Coat steak with coarse salt and let sit for at least 15 minutes, up to 2 hours. The salt brings out moisture which allows for a better sear. You should blot the steak with a paper towel before cooking. Bring steak to room temperature.
Preheat the oven to 425°.
Heat a cast iron pan on high heat over the stovetop. Melt butter in the pan. Gently lay the steak in the pan and cook for 4 minutes. Flip the steak and cook on the opposite side for 4 minutes.
Place the steak in a baking dish and then in the hot oven until the desired doneness. Cooking time will vary based on the thickness of the steak. (If you are using a thin steak you may not need to place it in the oven if you like it rare to medium rare)
When you finish cooking let it rest for at least 3 minutes before serving.