Classic Filet Mignon with Rich Bordelaise Sauce

Prepare the Bordelaise Sauce

1. 1In a medium saucepan, melt 1 tablespoon of butter over medium heat. Add the minced shallots and cook until softened, about 3-5 minutes. Add the minced garlic and cook for another minute until fragrant.
2. 2Pour in the red wine and bring to a simmer. Reduce the wine by half, scraping up any browned bits from the bottom of the pan. This will take about 10-15 minutes.
3. 3Add the beef stock, dried thyme, and bay leaf. Bring the mixture to a gentle boil, then reduce heat to low and simmer, uncovered, for 60-75 minutes, or until the sauce has reduced by two-thirds and is thick enough to lightly coat the back of a spoon. Skim off any impurities that rise to the surface periodically.
4. 4Strain the sauce through a fine-mesh sieve into a clean saucepan, pressing on the solids to extract all liquid. Discard the solids. Stir in the roasted bone marrow, if using, until it melts into the sauce.
5. 5Keep the sauce warm over very low heat. Just before serving, whisk in the remaining 2 tablespoons of cold butter, one cube at a time, until the sauce is glossy and emulsified. Season with salt and freshly ground black pepper to taste. Do not boil once butter is added.

Cook the Filet Mignon

1. 1Preheat your oven to 400°F (200°C). Pat the filet mignon dry with paper towels and season generously with coarse sea salt and freshly ground black pepper on all sides.
2. 2Heat olive oil in a heavy-bottomed, oven-safe skillet (preferably cast iron) over high heat until shimmering and almost smoking.
3. 3Carefully place the seasoned filets in the hot skillet. Sear undisturbed for 2-3 minutes per side until a deep brown crust forms. Reduce heat to medium-high if browning too quickly.
4. 4Reduce heat to medium. Add butter, crushed garlic, rosemary, and thyme sprigs to the skillet. Tilt the pan and spoon the melted butter and aromatics over the steaks continuously for 1-2 minutes to baste them.
5. 5Transfer the skillet to the preheated oven. Roast for 4-6 minutes for medium-rare (internal temperature of 130-135°F / 54-57°C), or longer for desired doneness. Use a meat thermometer for accuracy.
6. 6Remove the steaks from the oven and transfer them to a carving board or plate. Tent loosely with foil and let them rest for at least 5-10 minutes. This allows the juices to redistribute, ensuring a tender and flavorful steak.

Assemble and Serve

1. 1While the steaks are resting and sauce is finishing, lightly blanch asparagus in salted boiling water for 2-3 minutes until tender-crisp. Prepare potato purée as desired.
2. 2Slice the rested filet mignon if desired, or serve whole. Arrange on pre-warmed plates with potato purée and blanched asparagus.
3. 3Generously spoon the rich Bordelaise sauce over the filet mignon. Serve immediately.