Fillet of beef whole larder trim is the tenderest piece that you will ever find, it makes a wonderful beef wellington or dinner party centerpiece. Remember to seal the meat on top of the stove before cooking. A piece of meat 3 lb (1.36 kg) in weight will take no more than 45 min at 230°C gas 8 to reach med/rare. Also try brushing the meat with honey before you place the joint in the oven. This will give you a black rim to your beef as you slice through.
The undercut of the sirloin is probably one of the best-known and the most expensive of the cuts used for grilling and frying. It is known to be very tender, although it usually has less flavour than rump. The 'centre' or 'eye' of the fillet is considered the best part. The fillet is often cut and shaped into small rounds, known as Tournedos, weighing about 125 g (5 oz) each.
For reference, a fillet mignon is a small round steak, weighing about 75g (3 oz), cut from the end of the fillet.