“In this wonderfully extravagant showstopper the earthy porcini go hand-in-hand with the garlic, thyme and butter to really kiss the meat as it cooks, creating a flavour-packed meltingly tender treat. Wrapping the fillet in a parcel of prosciutto not only protects it, but also seasons it to perfection as it cooks. Double win! ”
Get the meat out of the fridge and leave to come up to room temperature before you cook it. Cover the porcini with 300ml of boiling water and leave to rehydrate for 5 minutes.
Peel and finely chop 2 of the garlic cloves, then place in a large frying pan on a high heat with a knob of the butter. Add the porcini and half the soaking liquor, then reduce the heat to low and simmer for 5 minutes, or until thick and syrupy.
Squeeze in the lemon juice, stir in the remaining butter, and season to taste with sea salt and black pepper. Leave to cool slightly.
Drizzle the beef with 1 tablespoon of oil and season with black pepper. Sear in a sturdy roasting tray over a medium heat on the hob until browned all over, then remove from the heat.
Lay out the slices of prosciutto on a large piece of greaseproof paper, overlapping them slightly, making a sheet big enough to wrap around the fillet.
Spread the mushroom mixture lengthways over one half of the prosciutto, then sit the beef on top. Carefully roll up, tuck in the ends, then discard the paper. Secure with butcher’s string.
Squash the remaining unpeeled garlic cloves and put into the roasting tray with the herbs, then carefully place the beef on top. Cook in the oven for 25 minutes for rare, 30 to 35 minutes for medium, or 40 minutes for well done.
When the time’s up, remove the meat to a board to rest for 5 minutes, pouring any juices back into the tray.
Transfer the tray to a medium-high heat on the hob, pour in the wine and the remaining porcini soaking liquor (discarding just the last gritty bit) and simmer to your desired consistency, scraping up all the goodness from the bottom of the tray.
Remove from the heat, and sieve before serving, if you like – I also like to whisk in an extra knob of butter for maximum silkiness.
Carve up the beef and serve drizzled with the red wine sauce – delicious with celeriac and potato mash, and steamed greens.