Preheat the oven to 225°F (107°C). Trim any excess fat or silver skin from the tenderloin.

Cut butcher’s twine into several pieces and tie the tenderloin at 1-inch intervals. To tie, slide the twine under the meat, bring the ends up, and tie a snug knot on top. Repeat along the length of the tenderloin.

Generously season the tenderloin all over with kosher salt and freshly ground black pepper, pressing the seasoning into the meat.

Place the tenderloin on a wire rack set over a baking sheet. Roast in the oven until the internal temperature reaches 120°F (49°C), about 1.5-2 hours.

Remove the tenderloin from the oven and cut off the butcher’s twine.

Heat 1 tablespoon olive oil and 3 tablespoons butter in a large skillet over medium-high heat. Once the butter is melted and bubbling, add the tenderloin, sliced garlic, thyme, and rosemary.

Sear the tenderloin on all sides, turning frequently, until a golden crust forms. Spoon the hot butter and oil over the meat as it cooks. Continue until the internal temperature reaches 125-130°F (52-54°C) for medium-rare.

Transfer the tenderloin to a cutting board and let it rest for 10-15 minutes. Slice into thick medallions and serve. Enjoy!