Salt and pepper for seasoning (or 1 tablespoon of crushed peppercorns)
Place your cast-iron skillet in the cold oven and pre-heat it to 500 degrees F.
Remove the steaks from the refrigerator and bring them to room temperature.
Rub them with the oil.
Season both sides with the salt and pepper (or the peppercorns).
Once the oven has reached 500 degrees remove the skillet and place it on a burner set to high heat. Let the skillet set for 4-5 minutes.
Once the skillet is ready, place the steaks in the middle of the hot, dry skillet. Let it sear for 3-4 minutes without touching! Then flip and sear the other side. (You are going for a very well-seared brown, crust.)
Place the skillet back in the oven. For medium, allow steaks to cook for an additional four minutes on each side, or until a meat thermometer reads 140 to 145 degrees F. (Adjust time by one to two minutes less for rare or more for well done.)
Remove the steaks, place on platter and add the butter (if using) to each steak. Allow steaks to rest for 5 minutes.
Checkout Ina’s Red Wine-Shallot Sauce to serve on top of steak: http://www.foodnetwork.com/recipes/food-network-kitchens/steak-with-red-wine-shallot-sauce-recipe/index.html