Mushroom filled beef fillet with port sauce

Christmas doesn't have to be all turkey and ham. Stun your guests with this earthy mushroom-filled beef fillet served with a rich port sauce.
1H 15M



1.Preheat the oven to 200°C (180°C fan-forced).
2.Place the porcini in a heatproof bowl; add 1½ cups hot water. Stand for 10 minutes, then strain over a jug. Reserve the liquid (about 1 cup). In a food processor, finely chop the garlic. Add the porcini, Swiss brown and cup mushrooms; process until the size ranges between a coarse breadcrumb and the fingernail of your pinkie.
3.n a large frying pan over medium-high heat, place 1 tablespoon of the oil. Add the mushroom and garlic mixture, thyme leaves, half the salt and pepper. Cook, stirring, for about 5 minutes. The mixture will initially release moisture, then the moisture will dry up and eventually turn golden and take on a paste-like consistency. Remove from the pan; cool.
4.Lay the beef fillet perpendicular to yourself on a board. Using a sharp knife, slice the meat lengthways toward you, about one-third from the left side and about two-thirds deep. Spread the small flap out to the left. Gently repeat this process with the large piece of meat on the right, butterflying and laying it out another 2-3 times so you have a fairly wide piece of meat.
5.Spread the cooled mushroom mixture over the meat and tie back into a roll with butcher’s string. Season the base then flip the roast uncut-side up in a heavy-based baking dish. Splash the remaining oil over and under the roast and sprinkle remaining salt and pepper on top.
6.Roast, uncovered, for 40 minutes. Cover with foil; rest for 30 minutes. Transfer roast to a carving board, keeping the roast covered in foil. Place the baking dish on the stove top over medium-high heat. Pour in the reserved porcini liquid and the port. Boil, while scraping any browned bits off the bottom of the pan. Cook to a syrupy consistency, then pour into a serving jug.
7.Slice beef thickly. Serve with the port sauce and watercress.
8.Not suitable to freeze or microwave. The recipe can be prepared to the end of step 4 a day ahead. Cover and refrigerate separately.