In a small bowl, whisk together kosher salt, coarse black pepper, smoked paprika, brown sugar, garlic powder, onion powder, ground cumin, chili powder, dried thyme, dried rosemary, mustard powder, and optional cayenne until evenly combined.

Oil the steaks

Lightly brush both sides of the steaks with neutral oil to help the rub adhere.

Apply the rub

Generously coat all sides of the steaks with the spice blend, pressing the rub into the meat to ensure even coverage.

Rest the meat

Let the coated steaks rest at room temperature for 15-20 minutes to allow the flavors to meld and the steaks to come closer to room temperature.

Preheat cooking surface

Preheat a heavy skillet (cast iron preferred) over high heat, or preheat a grill to high heat.

Cook the steaks

Cook steaks on the hot surface, about 3-5 minutes per side for 1-inch thick steaks for medium-rare. Adjust time by thickness and desired doneness.

Rest and serve

Transfer steaks to a plate and rest for 5 minutes before slicing to allow juices to redistribute.