Ingredients
Equipment
Method
- Tie the beef tenderloin with kitchen twine to ensure even cooking. Place the tenderloin on a wire rack set inside a baking sheet. Season generously with salt and pepper. Refrigerate uncovered overnight.
- Remove the beef from the refrigerator at least one hour before roasting. Preheat your oven to 225°F (107°C). Tuck fresh sage, rosemary, and thyme sprigs around the beef under the twine.
- Place the beef on the center rack of the preheated oven. Roast for 2.5 to 3 hours, or until the internal temperature reaches 120-125°F (49-52°C) for medium-rare. Remove from oven and let rest for 10 minutes.
- While the beef rests, melt the 6 tablespoons of butter in a saucepan. Adjust the oven rack to be about 6 inches from the broiler and preheat the broiler to high.
- Spoon some melted butter over the roast. Place it under the broiler, turning every 30 seconds and basting with more butter. Broil for a total of 2-3 minutes until golden brown. Remove from oven, drizzle with remaining butter, and let rest for another 10 minutes before slicing.
- For the Caramelized Onions: Heat a skillet over low heat and add 4 tablespoons of butter. Add the sliced onions and 1/2 teaspoon salt. Cook, stirring occasionally, for 45-60 minutes until caramelized and golden. Stir in 1/2 teaspoon fresh thyme after 45 minutes.
- For the Horseradish Sauce: Whisk together sour cream, heavy cream, prepared horseradish, mayonnaise, Dijon mustard, lemon juice, salt, and pepper. Stir in 3 tablespoons of chives. Let the sauce chill in the refrigerator for 30-60 minutes. Garnish with additional chives before serving.
Notes
Serve the sliced beef tenderloin with the caramelized onions and horseradish sauce.