Chateaubriand steak

Method

1. 1 Use a 5cm thick slice of sirloin and leave it out of the refrigerator for 1 hour to reach room temperature.
2. 2 Sear the meat in a very hot cast iron skillet for 3 minutes on each side, including the edges, until all six sides are seared.
3. 3 Preheat oven to 150 degrees for 12 minutes, then let it rest for 12 minutes. The thick block must cook through in the oven, not in the pan.
4. 4 Simmer shallots with white wine and tarragon until the liquid reduces to 2 tablespoons and thickens.
5. 5 Beat the cold butter in chunks over the lowest heat until it forms a light béarnaise sauce, then squeeze in some lemon juice.
6. 6 Slice the meat into 2 cm thick slices across the grain, then sprinkle with coarse salt and pepper, and serve with potatoes.

With an appliance

• Oven 50 min

  In step 3, bake the six-sidedly seared meat block on the middle rack of a 150-degree oven for 12 minutes, rotating the tray at the 7th minute, then let it rest for 12 minutes; steps 4 to 6 for making the sauce remain unchanged.