Remove steaks from refrigerator and season both sides with kosher salt and black pepper. Allow them to come up to room temperature for one hour.
Add 1 tablespoon of avocado oil to a cast iron pan, and preheat over high heat for 3-5 minutes.
Blot the steaks dry with a paper towel to remove any moisture. Then, place them in the pan, leaving about a two-inch space between the steaks. Sear for a total of five minutes, flipping them every 30 seconds.
Reduce to medium high heat, add unsalted butter, crushed garlic and rosemary to the pan.
Tilt the pan to one side so the butter pools, and continuously spoon it over top of the steak for one minute. This adds a depth of flavor and helps cook the steaks through.
Remove the steaks from the heat when they reach an internal temperature of 125°F as indicated by a quick read thermometer.
Allow steaks to rest for three minutes before topping each steak with one tablespoon of optional compound butter and serve.