1. Trim the tenderloin of any silver skin and excess fat. Tuck the long end under and use butcher’s twine to truss the tenderloin.
2. Season all over with salt and pepper and leave in refrigerator, uncovered overnight, or at least 10 hours. This will help cure the loin and give it a nice crust.
3. Preheat oven to 425F.
4. Place oil in a large cast-iron or heavy oven-proof skillet and heat over medium heat until hot. Sear the beef tenderloin on all sides, about 3–5 minutes per side, for a golden-brown crust. Let cool.
5. Combine the softened butter, garlic, horseradish and herbs in a bowl and mix well. Slather the seared tenderloin with the butter mixture. Using
the same skillet, place in oven. Roast 20–25 minutes. With a meat thermometer, roast to 120–125F for medium rare, 130-135F for medium.
6. Remove tenderloin from oven and transfer to a cutting board. Let rest for 15 minutes to allow the juices to redistribute before slicing.
Serves 6–8