Heat a cast iron skillet or other pan that can withstand high heat on high then add remaining butter. Be careful, it will sizzle quite a bit. Immediately put the steak in the pan and let sit undisturbed for 4 minutes. Flip steak and sear another 4 minutes. This should give you a medium rare steak that is caramelized on the outside. If you like your steak more done (I don’t recommend that), then leave on another minute or two. Let steak sit a few minutes before cutting.