Generously season steaks on both sides with kosher salt and freshly ground black pepper.
Drying Steak
If you have time, place the steaks on a wire rack placed over a rimmed edge baking sheet and refrigerate overnight, if not, go to Slow Roasting.
Slow Roasting
Pre heat oven to 200 °F, or lower if your oven will allow it.
Set steaks on a metal rack placed over a rimmed baking tray and roast until the internal temperature registers 130 °F, about 25 to 30 minutes for medium rare at an oven temperature of 200 °F. It will take longer at a lower oven temperature.
When the steaks have reached the desired internal temperature, remove from oven and heat a cast iron skillet over high heat until the skillet is hot, 2-3 minutes.
Add 1 tbsp butter to the skillet for searing the steak and sear for about about 45 seconds per side. The steaks should be nicely caramelized on each side.
Remove from pan and slice and serve. There is no need to rest the steak when using the reverse sear cooking method.
200 °F, or lower if your oven will allow it. 
