Côte de Boeuf with Béarnaise

Ingredients

• 1 côte de boeuf (2 bone-in ribs, cut 6 cm/2½ in thick), about 1.4 kg (3 lb)
• 2 tsp coarse salt
• 1 tsp black pepper
• 1 tbsp neutral oil
• 2 tbsp butter
• 3 sprigs thyme

Béarnaise

• 3 tbsp white wine vinegar
• 3 tbsp dry white wine
• 2 shallots, finely chopped
• 1 tbsp chopped fresh tarragon, plus 1 tbsp more for finishing
• 3 egg yolks
• 170 g (¾ cup) butter, melted and warm
• Salt and a squeeze of lemon

Steps

1. Salt and pepper the beef and leave it at room temperature for 1 hour.
2. Heat the oven to 120°C (250°F). Roast the meat on a rack for 40 to 50 minutes, until a thermometer reads 45°C (113°F).
3. Meanwhile, simmer the vinegar, wine, shallots and 1 tbsp tarragon in a small pan over medium heat until reduced to about 2 tbsp, about 5 minutes. Strain and cool slightly.
4. Whisk the yolks and reduction in a heatproof bowl set over barely simmering water, until pale and thick enough to leave a trail, 3 to 4 minutes. Take it off the heat whenever it starts to look scrambled.
5. Off the heat, whisk in the warm butter in a thin stream until thick and glossy. Season with salt and lemon, stir in the finishing tarragon, and keep warm (not hot) in a bowl of warm water.
6. Heat the oil in a large skillet over high heat until smoking. Sear the roast 2 minutes on each side and on the fat edge, adding the butter and thyme in the last minute to baste.
7. Rest on a board for 10 minutes; the centre will reach about 52°C (125°F).
8. Cut the meat from the bone, slice thickly against the grain, and serve with the béarnaise.

Notes

• Rescue: if the sauce splits, whisk in 1 tbsp hot water, a drop at a time.
• Serve soon: don't hold the warm egg sauce for more than about 30 minutes.
• Serving: pommes frites or gratin potatoes and a bitter green salad.
• Other cuts: the same method suits any thick bone-in ribeye.
• Make ahead: the vinegar and wine reduction (step 3) keeps 2 days in the fridge; whisk the sauce fresh.
• Chef's touch: finish the sliced meat with flaky salt; it sharpens the beef against the soft, buttery sauce.