In a small dish, combine all the spices with your fingers. Taste the mixture, and add more salt if you'd like.

Rub the spice mixture all over the steak on all sides. Let the steak rest on the counter while you preheat a cast iron or heavy skillet to medium-high heat. When the skillet is very hot, add the butter and let it foam and brown, then add the steak.

Cook the steak for about 4 minutes on each side for medium-rare, adjusting the time to cook the steak to your preference. Only turn the steak once, this will allow the spices to get crusty and cook into the meat.

When the meat is done, let it rest on a cutting board for 15-20 minutes, then thinly slice it. Save any juices that run out and pour over the steak before serving.

Serve with your favorite Mexican-style meal. Enjoy!