Preheat a grill to 225°F.
In a small bowl, mix together the rub ingredients. Using your hands, coat the steaks in olive oil and then generously sprinkle both sides with the rub. Allow the meat to rest at room temperature for approximately 30 minutes.
Place the steaks on the grill over indirect heat for approximately 22 minutes. Flip the steaks and cook for an additional 22 minutes or until the internal temperature of the meat reaches 120°F for medium rare. Remove the steaks from the grill and cover with foil. The meat will continue to cook as it rests under the foil.
Turn all of the burners on your grill up to maximum heat to get them as hot as possible. Once the grill is very hot, place the steaks back on the grill and sear for a few minutes, turning once. You are not looking to cook the meat at this point, but just to get a nice sear on the outside of the meat.
Remove the steaks from the grill, recover with foil, and allow to rest for 5-10 minutes.
For the sauce, process all ingredients in a blender until well combined.
To serve, slice the meat from the bone and enjoy with the chimichurri sauce.
This method will result in a medium to medium-rare cooked piece of meat. If you like your steak well done, continue to slow cook your meat until the internal temperature reaches 140°F and then follow the same method for searing.