Fillet differs to other cuts in that it is incredibly lean and has no protective fat to keep it moist. Fillet cooked to well done is exceptionally dry; for that reason, it is best served rare to medium. You can roast fillet in the same way that you would cook any other roast using our tips as a guide but the best way to cook fillet is 'en croute'; that is wrapped in pastry. Always bring meat to room temperature before cooking. Use cooking times and temperatures as a guide rather than a fact For the average 1kg whole fillet you would roast at a high-temperature 220C/Gas 7 for 20 minutes (rare) or 25 minutes (medium-rare). Use a meat thermometer for complete accuracy; a method far more popular in the domestic kitchen than you may think. 50C for rare 60C for medium Resting is essential. For all concerned. Left for half an hour the juices redistribute and the fibres relax; easy to carve tender to eat. Don’t worry about it going cold; it will keep itself warm and be all the better for it.