Take your steaks out of the fridge about 1 hour before you're ready to cook to bring them up to room temperature.

Put your cast iron skillet in the oven, then preheat to 500 degrees F. Make sure your kitchen is well ventilated. It's going to get very very smokey!

In a small bowl, mix ground coffee, cocoa powder, brown sugar, garlic powder, salt, pepper, paprika and ground mustard.

Smear butter all over the steaks.

Pour a generous amount of the coffee dry rub on each side of the steak.

Turn on your stove's burner. Using oven safe gloves, take your skillet out of the oven and place it on the burner.

Place the steaks on the skillet. 30 seconds on each side.

Using oven safe gloves, place skillet back in the oven and let the steaks cook 2 minutes per side (medium rare...for well done, add 1 minute to each side).

Remove steaks from skillet and put them on a plate.

Let sit for at least 5 minutes (under tin foil) before cutting into steak.