6 g (2 1/2 tsp) fresh thyme or 2.5 g (1/2 tsp) dried thyme
salt and pepper
1 beef fillet, weighing about 1 kg (2 lb)
15 g (2 tbsp) chopped parsley
450 g (1 lb) puff pastry
1. To prepare the marinade, peel and crush 3 of the garlic cloves and mix with 30 ml (2 tbsp) of the oil, the wine, spring onions, 5 g (1 tsp) of the mustard, the thyme, and plenty of salt and pepper.
2. Lay the fillet at the bottom of a large plastic bag and pour the marinade over it. Seal the top of the bag, put it on a plate in case of leaks, and leave to marinate in a cool place for 6 - 8 hours.
3. Heat the remaining oil in a large frying pan until very hot.
4. Lift the meat out of its marinade and fry it quickly on all sides to seal in the juices; this should take no more than 2 minutes.
5. Cool the beef and return to its marinade. Freeze for an hour — more if you like your fillet really rare.
6. Simmer the remaining unpeeled garlic cloves for 20 to 25 minutes, until soft. Drain, peel and mash with a fork to a sticky paste.
7. Stir in the remaining mustard and the parsley, and season with salt and pepper to taste.
8. Take the beef out of the freezer and leave, to thaw the marinade. Roll out the pastry to a thickness of 0.5 cm (1/4 in) — large enough to wrap the beef generously.
9. Drain the meat and add 15 ml (1 tbsp) of its marinade to the garlic and parsley mixture.
10. Lay the beef in the middle of the pastry and spread the garlic and parsley mixture over it.
11. Wet the edges of the pastry with a little water, bring them up over the sides of the meat, and press them together. Seal the ends.
12. Put the pastry-wrapped beef, seam side down, on a well greased baking tray, brush the top with a little milk or egg yolk, and bake for 15 to 20 minutes at 230°C ( 450°F) Gas 8, until the pastry is cooked. If, after this time, the pastry is cooked but the fillet is too rare turn down the heat to 190°C (375°F) Gas 5. and cook for a further 7 to 10 minutes, and test again. Serve immediately.