Remove the steaks from the refrigetor about an hour before cooking. Season liberally with kosher salt and freshly cracked black pepper.
Preheat the oven to 425º F.
Add the butter and olive oil to a cast iron skillet and heat over medium-high heat until it's screaming hot and beginning to smoke a little. Add the room temperature, seasoned steaks to the skillet and sear untouched for about 4 minutes (until a nice crust has formed). Flip and repeat. Once the 2nd side has the perfect crust, transfer the pan seared filets to the preheated oven and roast for about 6 - 10 minutes, depending on the thickness of the steak and the desired temperature. The steaks will continue to cook once removed from the oven so you want to take them out when the thermometer reaches about 5 degrees below your desired temperature. (See notes for temperature guide)
Remove from the oven, transfer to a plate, tent in foil and allow to rest for about 10 minutes before serving or cutting.
Drizzle with Roasted Garlic Aioli and garnish with Rosemary or Thyme, if desired.
Roasted Garlic Aioli
Note: This can be made up to 3 days beforehand and kept in the refrigerator. Preheat the oven to 425º F.
Rub the outside of the heads of garlic to remove the majority of the white paper-like skin. Cut the tops off of the heads of garlic and drizzle with olive oil and season liberally with kosher salt.
Roast for 30 minutes or until the tops of the cloves are golden brown and they feel soft. Allow to cool until they can be handled.
Add mayonnaise, lemon juice, rosemary and thyme to a small blender or small food processor. Squeeze the roasted garlic to remove soft insides of the garlic cloves and add to mixture. Blend. Drizzle over steak (and asparagus and potatoes if you're so inclined!)
Notes
Steak Temperature Chart(Remove once grilling thermometer reaches about 5 degrees below your desired temperature)Medium Rare: 145º FMedium: 160º FWell Done: 170º F