Côte de Bœuf with Béarnaise Sauce

Remove the côte de bœuf from the refrigerator and pat completely dry with paper towels. Season aggressively on all sides — including the fat cap and bone — with flaky sea salt and black pepper.

Rest the seasoned beef uncovered at room temperature for 45–60 minutes.

Make the béarnaise reduction: combine the white wine, white wine vinegar, minced shallots, crushed peppercorns, and the first tablespoon of tarragon in a small saucepan over medium heat. Simmer until reduced to about 2 tablespoons of liquid, then strain through a fine sieve, pressing the solids; discard the solids and let the reduction cool completely.

Clarify the butter: melt the 250g butter in a small saucepan over low heat without stirring until the milk solids sink and the golden fat is clear on top. Skim the foam and carefully pour the clarified butter into a jug, leaving the white solids behind; keep it warm but not hot, around 60°C.

Preheat the oven to 120°C (fan 100°C / gas ¼). Place the beef on a wire rack set over a rimmed baking tray and roast gently until nearly cooked through — this low, slow stage builds an even doneness gradient before the final sear.

Remove the beef from the oven and rest on the rack, loosely tented with foil, for 15 minutes while you sear and make the béarnaise.

Place a cast-iron skillet over the highest heat possible for 3 minutes until it begins to smoke. Add the neutral oil, then lay in the côte de bœuf; sear without moving until a deep mahogany crust forms, about 90 seconds per side, then stand the steak upright with tongs to render the fat cap for a further 60 seconds. Add the butter, tilt the pan, and baste continuously for 30 seconds. Use a meat thermometer to confirm the internal temperature has reached 63°C (medium) before removing.

Make the béarnaise: set a heatproof bowl over a saucepan of barely simmering water, ensuring the bowl doesn't touch the water. Add the egg yolks and the cooled reduction and whisk vigorously until pale, thick, and holding a ribbon, about 3–4 minutes.

Remove the bowl from the heat and, whisking constantly, pour in the warm clarified butter in an extremely thin, steady stream — drop by drop at first, then in a thin thread — until fully incorporated and the sauce is thick enough to coat the back of a spoon. Season with salt and cayenne, then fold in the remaining tablespoon of tarragon and the chervil. Keep warm over the hot water with the heat off.

Carve the côte de bœuf away from the bone, slice against the grain into 1.5cm portions, and serve immediately alongside the béarnaise.