- 25g (1oz) dried wild mushrooms
- 200g (7oz) button mushrooms
- 2tbsp olive oil plus a little extra
- 1 onion, finely chopped
- 2 garlic cloves, finely chopped
- 1 piece beef fillet, weighing between 1.2g (2lb 12oz) and 1.5kg (3lb 6oz)
- 12 to 14 very fine slices Serrano ham*
- *Pre-packed Serrano ham from the supermarket is best for this. Hand-cut is too thick and makes it hard to stick to the beef. Otherwise, substitute pre-packed Parma ham.
Soak the dried mushrooms in boiling water for 15 minutes, then drain through a sieve. Put the button and wild mushrooms into a food processor and pulse until finely chopped, but not a purée.
Heat the oil, reserving a little for later, and fry the onion until soft but not coloured. Add the garlic and cook for few minutes. Stir in the mushrooms and cook for about 30 minutes over a very low heat until the mushrooms have given off any excess liquid and are reduced. Taste then season with freshly ground black pepper. Set aside to cool.
Trim any excess fat off the fillet, then season it with salt and pepper. Add a little oil to a large frying pan or use a roasting tin on the hob. Heat through then brown the fillet all over. Let it cool.
Roll a large piece of clingfilm out onto a big chopping board – this will make the beef much easier to roll. Now lay out a rectangle of the Serrano ham, 2 slices by 5 slices, slightly overlapping in the centre of the clingfilm. Place a quarter of the mushroom mixture on top in a line down the centre. Place the fillet on top of the mushrooms. With a knife, spread the remaining mushrooms all over the fillet, covering it completely in a thin layer of the mixture. Now use the clingfilm to help roll up the beef, lifting it carefully and rolling it up. The ham will stick to the beef. Keep the clingfilm on the outside so it’s easy to unroll. When rolled, twist the ends to tighten the roll, then transfer the whole thing to a plate and refrigerate for at least 4 hours or overnight.
Preheat the oven to 200 C, 180 C fan, 400 F, gas 6. Let the beef come back to room temperature (about 30 minutes) then unwrap and discard the clingfilm, put the beef into a roasting tin, rub a little oil over and some freshly ground black pepper, then roast for 25 minutes for rare, 35 minutes for medium and 45 minutes for well done.
Remove from the oven and leave to rest for 10 minutes or so, then, using two fish slices and an extra pair of hands, transfer to a chopping board. Carve into slices with a very sharp knife, place on a platter and drizzle over any juices from the tin. This needs nothing more than a squeeze of lemon juice or some Dijon mustard to accompany.