One of my favorite ways to cook a steak is in a cast iron skillet. I preheat my oven to 500 degrees with the skillet inside. While the oven is preheating, I take the steak out and season it with salt and cracked black pepper.
Now, let's talk about fats. Not all fats are created equal. Cooking a steak in butter is delicious but butter burns at the type of temperatures that we need to get a great sear going. Olive oil also has too low of a smoking point - so that leaves us with a few choices... high heat vegetable oils (and they are great) or rendered animal fats (they are awesome).
If I have it, I like to sear my steaks in rendered duck fat. Because duck fat is such a silky, delicious, wonderful fat.
Optional - if you have enough, you can coat your seasoned meat in the rendered fat before cooking for extra awesomeness!
So, now, the oven has come to temp (I always let it sit at temp for an extra 15 min) and you have seasoned and taken the chill of of your meat (there are different schools of thought on this too - some people believe that it's better to sear from cold. I've tried both, I like the results I get when it comes to temp first. Try it and see which works better for you). It's time to take the skillet out of the oven and put it on a burner at the highest setting.
Add your fat to the pan. Then place the steak in the middle of the pan and let it sear. I leave it alone for about 4-6 minutes, depending upon how thick the steak is, and how quickly it cooks (supermarket meats have a lot of preservatives in them so they will cook faster).
Then, flip the steak over and put the pan back into the oven. I like mine medium rare. My boyfriend prefers them medium well. The best way to check them is with a probe thermometer. I tend to check based on the pressure it gives me when it bounces back because I don't like poking extra holes in the meat while it's still cooking but if you are new to this, use the thermometer.
When it comes out of the oven, it's going to smell awesome! Don't touch it. Take the steak out of the pan and let it rest on a warm plate while you decide what kind of pan sauce you want to make.
You have all this beautiful fat that the bottom of your pan -- why waste it. The options are endless. You can saute mushrooms and onions in it. You can add red wine (as I did below) and reduce it to a syrup. You can add a touch of flour and some beef stock and make a gravy, or you can just dab the top of the steak with butter and let it soak in while it rests.
After 15 - 20 minutes of resting in a warm place, you can serve your steak and eat!