Filet Mignon Steak Frites Recipe

Make the compound butter

In a medium bowl, combine the room-temperature unsalted butter, finely minced shallot, chopped chives, chopped parsley, Dijon mustard, lemon juice, Worcestershire sauce, sea salt, and freshly ground black pepper. Use a fork to mash and blend until homogeneous and smooth.

Scrape the butter mixture onto a piece of plastic wrap or parchment paper. Shape into a log about 1–1.5 inches in diameter, turning the wrap as you roll to create a tight cylinder. Twist the ends to seal. Refrigerate for at least 1 hour to firm up, or freeze for 15–20 minutes if you need it sooner.

When firm, slice into 1/2-inch rounds to serve atop steaks. Keep chilled until ready to finish steaks.

Prepare and par-cook potatoes

Peel (optional) and cut russet potatoes into 1/3-inch to 1/2-inch sticks. Place cut fries in a large bowl of cold water and rinse until water runs clear to remove excess starch. Soak for 30 minutes (or refrigerate up to 2 hours) to further remove starch; this yields crisper fries.

Drain and dry potatoes thoroughly on clean kitchen towels. Pat completely dry to avoid oil splatter.

First fry (blanch)

Heat vegetable oil in a heavy-bottomed pot or deep fryer to 300°F (150°C). Working in batches, fry the potatoes 3–4 minutes until soft and pale (not golden). Remove with a slotted spoon to a wire rack or paper towels and let cool. Increase oil temperature to 375°F (190°C) for final fry.

Final fry & season

When oil reaches 375°F (190°C), fry the par-cooked fries in batches until golden and crisp, about 2–3 minutes per batch. Transfer to a wire rack or paper towels, immediately season with sea salt and freshly ground black pepper, and toss with chopped parsley if using. Keep warm in a single layer in a low oven (200°F / 95°C) while you cook steaks.

Bring steaks to room temperature and season

Remove filets from refrigerator about 30–45 minutes before cooking to bring to room temperature. Pat dry with paper towels. Generously season both sides with kosher salt and freshly ground black pepper.

Sear and baste

Heat a heavy skillet (preferably cast iron) over high heat until smoking hot. Add 2 tbs neutral oil and swirl to coat. Add the filets (do not crowd the pan). Sear without moving until a deep brown crust forms, about 2–3 minutes. Flip and add 2 tbs unsalted butter, crushed garlic cloves, and thyme sprigs. Tilt the pan and spoon the melted butter, garlic, and thyme over the steaks repeatedly (baste) for 1.5–3 minutes, or until the internal temperature reaches your target (120–125°F / 49–52°C for rare, 125–130°F / 52–54°C for medium-rare).

Rest the steaks

Transfer steaks to a cutting board and top each with a slice of chilled Chateaubriand butter. Tent loosely with foil and let rest for 5–7 minutes; internal temperature will rise a few degrees and butter will melt into the meat.

Place a filet on each warmed plate alongside a generous portion of fries. Spoon any accumulated resting juices from the cutting board over the steak.

Top each steak with an additional pat of Chateaubriand butter if desired and sprinkle a pinch of coarse finishing salt over the meat for texture. Serve lemon wedges on the side for those who prefer a bright finish.

Serve immediately so fries remain crisp and compound butter is melted into the steak.