Fill a large pot with water. Attach your sous vide machine to the side, then set the temperature to 130 degrees for medium rare.

Season the steaks on both sides with Kosher salt and pepper. Place them in a quart or gallon size zip lock bag, and top with the crushed garlic and rosemary.

Seal the bags about ¾ of the way, then slowly lower them into the preheated water, letting the pressure of the water push out excess air around the steaks. Once the bag is submerged, seal it completely, then clip it to the side with a chip clip or clothes pin. Set the time for 1 hour. The steaks can be left in the water for up to 4 hours without impacting the texture or flavor.

Remove the steaks from the bag, brushing off any garlic or rosemary and setting it aside.

Heat the oil in a cast iron skillet over high heat. Add the steaks and sear, undisturbed, for 1-2 minutes, or until a golden crust has formed. Flip the steaks over.

Add the butter to the pan, along with the garlic and rosemary. Use a hot pad to tip your pan so the butter collects on one side. Use a big spoon to scoop and drizzle the butter over the steak for about 1-2 minutes.

Serve the steaks with the pan juices.