Directions

1. Put the beef in a container just big enough to fit snugly. Mix the marinade ingredients in a bowl and tip over the beef. Cover and chill, turning and basting as often as possible. Leave for 24-72 hrs.
2. Pour the Port and wine into a large pan and simmer until reduced to a glaze. - this will take about 20 mins. Heat the oil in a separate large pan and, when almost smoking, add the beef scraps and cook until dark golden. Add the shallots, garlic, peppercorns and herbs. Fry for a few mins until starting to brown, then add the reduced alcohol and stock. Bring to a simmer and cook for 25 mins. Strain into a clean pan, then simmer for 8-10 mins until thickened. Season to taste and chill until needed.
3. Heat oven to 200C/180C fan/gas 6. Remove the fillet from the marinade and brush off the herbs, reserving them and the garlic for later. Heat the vegetable oil in a large pan. When almost smoking, add the fillet, season with 2 tsp salt and fry for 5-7 mins, turning every so often.
4. Add the butter, cube by cube, and - when foaming - baste the fillet, turning regularly. When the fillet is caramelised, put in a roasting tin with the reserved herbs and garlic, and cook in the oven for 8-12 mins, turning every 4 mins and basting. To check that the beef is done, insert a probe thermometer into the centre - it should read 55-60C for medium rare. Transfer to a board, wrap loosely in foil and rest for 20 mins.
5. Return the tin to the oven until the butter is hot. Before serving, roll the fillet in it. Serve with the sauce, croquettes, carrots and garlic.