The meat is simply left in the cider to marinate with the juniper berries and garlic cloves for at least 2 hours. Cooking is done by draining and drying the meat and sealing in a very hot pan with 2 tbsp butter and then seasoning and roasting on 200?C/400F/gas mark 6 for 10-15 minutes, depending on the thickness of the fillet, to achieve a medium-rare centre. There is not much fat in the meat and you should take care not to overdo it or it will dry out and loose its juices. The celeriac is cooked in the chicken stock until soft (about 10 minutes if the vegetable is not too ?woody? in texture) and then mashed with a fork. You can use a mouli-legumes if desired, but a rustic feel to this dish is perfectly acceptable. Add the cream for smoothness, season and keep warm for the meat to arrive. The mushrooms are simply sauted in butter and seasoned. The sauce is made by sauteeing the onion, celery and carrots until soft and then seasoning, adding sugar, berries and some of the cider from the marinade. This should all cook down into a smooth puree (if desired you can pass the saute through a coarse sieve). Check the sugar and salt levels to ?balance? the acidity of the wild cranberries. To assemble, let the meat rest for 5 mins to let the fibre ?relax? (reserve any drained juices for the sauce) and slice thickly and place over the creamed celeriac. Arrange the mushrooms around the outside of the meat and pour the fruity sauce over and around the plate.