Salt both sides of steaks with 1/2 teaspoon Diamond Crystal kosher salt per steak. Place steaks in an airtight container and refrigerate 48 hours.

Remove steaks from the refrigerator about 30 minutes prior to cooking. Sprinkle both sides of steaks with black pepper.

Heat a cast-iron skillet over medium-high heat until very hot. Add vegetable oil; heat until oil shimmers.

Carefully place steaks in skillet. Cook until brown and hard-seared on one side, 4 to 5 minutes.

Flip steaks; top with 1 teaspoon butter. Cook until desired doneness, or 3 to 4 minutes more. You may need to cook steaks in batches depending on the size of your cast-iron skillet. Keep cooked steaks in a 170 degrees F ( 77 degrees C) oven until ready to serve.