Herb-Crusted Beef Tenderloin with Red Wine Demi-Glace, Truffle Mashed Potatoes and Balsamic-Glazed Brussels Sprouts

Remove beef tenderloin from refrigerator 1 hour before cooking to bring to room temperature. Pat completely dry with paper towels.

Preheat oven to 250°F (121°C) and position rack in center of oven.

Strip leaves from 2 sprigs of rosemary and 3 sprigs of thyme. Finely chop the herbs and set aside.

Peel and mince 3 garlic cloves. Crush the remaining garlic clove and set aside for the sauce.

In a small bowl, mix 1 tablespoon Dijon mustard with the minced garlic, chopped herbs, 1 teaspoon crushed black peppercorns, and 1 teaspoon kosher salt.

Rub the beef tenderloin with the herb-mustard mixture, coating all sides evenly.

Place an oven-safe wire rack on a rimmed baking sheet. Put the tenderloin on the rack.

Insert a meat thermometer into the thickest part of the tenderloin if using.

Roast beef in the preheated oven until internal temperature reaches 120-125°F (49-52°C) for medium-rare, about 30-40 minutes.

While beef is roasting, prepare the sauce. Peel and finely dice 1 medium shallot.

Heat 1 tablespoon olive oil in a saucepan over medium heat. Add diced shallot and crushed garlic clove. Sauté until shallot is translucent, about 3-4 minutes.

Add 1 cup red wine to the saucepan and increase heat to medium-high. Simmer until reduced by half, about 10 minutes.

Add 1.5 cups beef stock and continue simmering until reduced to about 1/2 cup of liquid, about 20-25 minutes. The sauce should coat the back of a spoon.

Strain the sauce through a fine-mesh sieve into a clean saucepan. Return to low heat and whisk in 1 tablespoon cold unsalted butter. Season with remaining 1/2 teaspoon kosher salt and keep warm.

For the potatoes, peel 1 pound of russet potatoes and cut into 1-inch cubes. Rinse under cold water.

Place potatoes in a large pot and cover with cold water by 1 inch. Add 1/2 teaspoon salt. Bring to a boil over high heat, then reduce to medium and simmer until fork-tender, about 15-20 minutes.

While potatoes are cooking, warm 1/3 cup milk in a small saucepan until steaming but not boiling.

When the beef reaches target temperature, remove from oven and let rest for 10 minutes. Increase oven temperature to 450°F (232°C).

While oven is heating and beef is resting, prepare Brussels sprouts. Trim stems and remove any discolored outer leaves. Cut in half lengthwise.

Toss Brussels sprouts with 1 tablespoon olive oil and a pinch of salt. Arrange cut-side down on a baking sheet.

Roast Brussels sprouts in the 450°F oven for 15 minutes until edges are crispy and caramelized.

In a small bowl, mix 2 tablespoons balsamic vinegar with 1 teaspoon honey.

Return beef tenderloin to the 450°F oven for 5-7 minutes to develop a crust.

Drain potatoes thoroughly and return to the hot pot. Allow excess moisture to evaporate for 1 minute.

Mash potatoes with a potato masher or ricer. Add warm milk, 2 tablespoons butter, and 1 teaspoon truffle oil. Stir until smooth and creamy.

Remove Brussels sprouts from oven and immediately drizzle with the balsamic-honey mixture. Toss to coat evenly.

Remove beef from oven and let rest for 5 minutes before slicing.

Slice beef tenderloin against the grain into 1/2-inch thick medallions.

Finely chop 2 tablespoons fresh parsley for garnish.

To plate, place a mound of truffle mashed potatoes on each plate. Arrange beef medallions alongside. Spoon red wine demi-glace over the beef. Add Brussels sprouts to the plate and garnish with chopped parsley.