This Roast Beef Tenderloin starts low and slow in the oven and ends with a flourish on the stove. It's a great recipe to pull out for holidays, parties, and Sunday Supper.
In a small bowl, add butter, shallot, parsley, garlic, and salt and pepper to taste (I like 1/4 teaspoon salt and 1/4 teaspoon pepper). Chill until it's time to sear the beef.
To make the beef:
Using 12-inch lengths of kitchen twine, tie the roast crosswise at 1 1/2-inch intervals. Sprinkle tied roast with salt, cover loosely with plastic wrap, and let stand at room temperature for 1 hour.
Adjust an oven rack to the middle position and preheat oven to 300 degrees. Set a wire rack over a rimmed baking sheet (line the baking sheet with foil for easier cleanup).
Pat roast dry with paper towels, then sprinkle evenly with pepper and rub with butter. Transfer roast to prepared rack.
Roast until beef registers 125 degrees (for medium-rare), 40 to 55 minutes or 135 degrees (for medium), 1 hour to 1 hour and 10 minutes. Flip the roast halfway through cooking.
In a large skillet over medium-high heat, heat vegetable oil until just smoking. Add roast to skillet and sear until well-browned on all sides, about 2 to 4 minutes per side.
Transfer roast to a carving board and spread 2 tablespoons shallot butter evenly over the top. Let roast rest for 15 minutes.
Remove twine and cut roast crosswise into 1/2-inch thick slices. Serve, passing remaining shallot butter separately.
Notes
Beef tenderloin: Center-cut beef tenderloin, also known as Châteaubriand, has a thick layer of fat that needs to be removed before roasting.
To trim the fat: Slide tip of knife just under connective tissue, keeping the knife tip close to surface of the meat to minimize meat loss. Use your other hand to pull connective tissue tight against the blade, then slide the knife angled away from the meat.
To tie the roast: Use kitchen twine to loop around one side of the tenderloin and tie a snug knot. Loop the string around your left hand and pull that loop over your tenderloin. Repeat the loops, spacing 1 1/2-inches apart and tightening each one snugly. Tie off the end with a knot.