Preheat a water bath to 80°C

To begin, prepare the potato röstis. Season the grated potato generously with salt, mix well and place in a colander. Leave over a bowl or sink for 15 minutes to drain, then transfer to a clean tea towel and squeeze out as much moisture as possible

Place the potato in a mixing bowl. Melt the duck fat, pour over the potato and mix well

Place the mixture in a large vacuum bag, seal in a chamber sealer then place in the water bath for 4 hours

To make the red wine sauce, place the butter in a large saucepan and melt over a medium heat. Add the onion and garlic, cook until deeply caramelised then add the mushrooms. Continue to cook until the mushrooms are also caramelised

Deglaze the saucepan with the red wine, increase the heat to high and reduce the sauce by half. Add the remaining ingredients and simmer over a medium heat until reduced to a deep, glossy sauce. Skim the surface of the sauce as it reduces to remove any impurities and fat

Pass through a fine sieve then pass through a muslin cloth. Set aside until ready to serve

For the clementine purée, peel the clementines and place the peel in a saucepan, cover with cold water and bring to the boil. Simmer gently for 20 minutes, then strain the peel and return to the saucepan. Repeat this process 2 more times in order to remove the bitterness from the peel

In a separate saucepan, gently heat the sugar, water and olive oil until the sugar has dissolved. Place the strained, cooked peel (after its third boiling) into a blender with the sugar syrup and blitz until smooth. Pass through a fine sieve and store in the refrigerator until required

Allow the potato rösti mix to cool completely before removing from the vacuum bag and cutting into 4 even triangles

Reduce the temperature of the water bath to 57°C

To make the juniper seasoning, grind all of the ingredients into a fine powder with a pestle and mortar or blender. Set aside

Place the venison loin in a vacuum bag and seal in a chamber sealer. Cook in the water bath for 30 minutes

Preheat a chargrill pan or barbecue until hot

For the charred clementines, cut the clementines into 4 x 1cm slices. Lightly brush with olive oil and char on the pan or barbecue for 1–2 minutes on each side. Keep warm until ready to serve

Blanch the kale in boiling salted water for 2–3 minutes, or until tender

To finish the röstis, melt a little duck fat in a frying pan and sauté the röstis until crisp and golden

Remove the venison from the vacuum bag and sear in a very hot frying pan with a little oil for 1 minute either side. Season generously with the juniper seasoning and sea salt. Allow to rest for a few minutes, then carve into 20 slices

To serve, swirl the purée along the edge of the plates. Stand up a triangle of rösti, add a slice of charred clementine and a small pile of kale to each plate. Place 5 slices of venison on top of the kale and sprinkle over the grated chocolate

Finally, pour over the red wine sauce, allowing the clementine purée to contain the sauce in the centre of the plate