Tenderloin

Beef tenderloin is the long, tapering muscle that runs along the inside of the spine beneath the ribs, the psoas major, and it is the most tender cut on the animal because it does almost no work. A whole one weighs two to three kilos and yields a chateaubriand from the thick centre, filet mignon medallions from the narrower section and a tail that is diced or minced; the French call the whole piece the filet, the British fillet, and the Americans sell both the whole roast and the steaks under the tenderloin name. The same muscle sits inside the T-bone and porterhouse opposite the strip. Its reputation and price rest on texture alone: it has little intramuscular fat and a mild flavour, which is why classical cooking wraps it in bacon, pairs it with béarnaise, pepper sauce or a red wine reduction, buries it in pastry as beef Wellington, or serves it raw as tartare and carpaccio, where tenderness is the whole point.