Ingredients
6lbsbeef tenderlointrimmed
3tspcoarse salt
1½tspfresh cracked black pepper
2tbspcanolaor vegetable oil
½cupunsalted butterdivided
4largecloves garlicminced
½tspDijon mustardoptional
2tbspvegetable oilor canola oil
1onionor brown shallots, finely chopped
1½cupsdry red wineMerlot or Pinot Noir
2cupsbeef stock or broth
1sprigfresh thyme
⅛tspground black pepper
¼tspsalt
Preparation
Slice tenderloin in half crosswise to create 2 smaller roasts. If the roast is untied, fold ends up against the center or thicker part of each roast and tie with kitchen twine spaced about 1-inch apart. Make sure each half is even in thickness.
Chill in the refrigerator, uncovered, for 12 hours (if time allows)
Let beef stand at room temperature for 1-2 hours before roasting.
Arrange the oven rack to the middle of your oven and preheat to 430°F.
Season each beef tenderloin roast all over with salt and pepper. Heat the oil in an oven-proof skillet over medium-high heat until hot.
Sear roasts on all four sides for about 3 minutes on each side (about 12 minutes total), turning with tongs until well browned.
Combine butter, garlic, and Dijon (if using) together in a small bowl while roasts are searing. Set one half of the butter mixture aside to use later for the sauce.
Slather remaining garlic butter over each roast (about 2 tablespoons each).
Transfer skillet into the hot oven or transfer roast to a lightly greased roasting pan or baking dish.
Roast for about 20 to 25 minutes until an instant-read thermometer inserted into the thickest part registers 120 to 125 degrees F for medium-rare.
Transfer the roast to a carving board and let rest for 15 minutes. Keep the juices in the pan to make the sauce.
Carve the beef tenderloin into ½-inch-thick slices and serve the beef tenderloin with the optional red wine sauce.
Skim fat off the remaining juices in the pan (if any).
Heat oil in the same pan with remaining pan juices over medium-high heat. Sauté onion for about 3 minutes until lightly browned and softened, scraping up any browned bits left from the beef.
Add thyme or rosemary and season with pepper. Continue cooking for 1 minute more or so while stirring often.
Pour in red wine and cook until reduced by half.
Add in beef stock and bring to a boil. Reduce heat and simmer until reduced by half. Remove the sprig of thyme or rosemary.
Season with salt to taste and whisk in reserved garlic butter. Pour in any juices left from the resting steaks just before serving. Strain sauce through a sieve and discard the onion before serving.
