All time favourite.
heat oven to 475f
Spread the top with Dijon mustard and the grind pepper. Its a good idea to seive it to get rid of the dry, over the top powdery chafe. Press the pepper over the mustard.
Make a trivet with onion halves,Face down.(that way they'll brown and add yum and colour) Celery and carrots. This will give you a rich gravy.
Put the meat on the trivet of veg at give it 20 mins.
Turn the heat down to 375 and give it 15 mins a lb then another 15 for rare. 30 for medium and 45 for well done.
Baste as often as you remember. The more the better
Take it out and cover tightly with foil. It'll stay hot for an hour easily and it needs to rest.
Take the veg out and consider them cooks perks with a shake of salt.
Deglaze the pan with 1/2 a glass of red wine, Add a glass of water or beef stock. Reduce slightly and thats it. If you want a really rich gravy, whisk in a few knobs of ice cold butter. Season.