The spice blend for ribeyes or steaks will keep in a ziplock bag or airtight tin for months.
1. In a dry pan, toast all ingredients over medium heat for 2 to 3 minutes, until cumin starts to darken and you can smell the spices release their aromatics. The ancho chiles will also darken in spots. Keep the pan moving constantly so that you don’t burn any of the ingredients. Transfer all the ingredients to a bowl and let cool, then grind in batches until slightly coarse in a spice grinder. (A coffee grinder solely dedicated to spice-grinding works as well.)
2. Sprinkle mixture liberally over steak and pat into meat, making sure to get the edges. Let the steak rest for 10 to 15 minutes while you fire up the grill.
3. Brush steak with clarified butter and grill to desired temperature, basting with butter when turning it over. The spices will darken and char a bit. To get a medium-rare steak, grill 3 to 5 minutes per side on high heat, time varies depending on thickness of steak. Alternately, use a meat thermometer and grill to 140 to 145 degrees internal temperature for medium-rare.
4. Let steak rest under a tent of foil for at least 5 minutes before serving. Finish with coarse salt to taste.