Remove the bark from the saddle, trim away excess fat. Turn the saddle upside down and remove the fillet on the under carriage, trim and remove the fat from the fillet. Remove the chine bone keeping the saddle intact. Then bat the fat with a mallet to minimise the thickness of the fat, trim the edges to form a rectangular shape approx. 45cm x 20cm long on the loin fillets which remain intact to the rest of the fat.
Spread a layer of the foie gras mousse in between the fillets then lay the fillet of lamb on top, continue this process once more. Saute the foie gras medallions then chill. Place the chilled Foie Gras on top of the mousse then repeat the process with the mouse and lamb fillet, finally spread with mousse once again
Lightly roll the flaps of the saddle so they overlap, form into a round shape, cover ends with strips of coil fat then string the whole saddle. Chill for 20 minutes.
Roasting the Saddle
In a roasting tray, render and seal the fat on the outside of the saddle then place in an oven at 180°C for 25 minutes. Allow to rest in a warm area for 25 minutes. Remove coil fat, then slice across lamb in 8mm thick to reveal the mosaic.
Cut the mushrooms into fine dice, sweat with the shallots and a clove of garlic, sauté until tender and allow to cool. Dice the chicken breast and foie gras then place into blender, puree with egg white. Place the bowl over ice and continue to mix thoroughly whilst adding the cream. Season to taste. Pass through a fine sieve and add the chopped herbs and the cooked, diced mushrooms.
Place the trimmings into a pan and caramelise slowly. Add the mirepoix and aromats, caramelise once again. Deglaze with Madeira and white wine. Add the chicken stock and bring to the boil, skim then simmer for approx. 1 hour. Pass through a sieve, reduce to consistency. Season and finish by whisking the beurre noisette into the finished sauce.
Prepare the vegetables in the normal way and blanche in salted, boiling water until quit tender. Chill and reserve.
Boil potatoes in their jackets with salted water for approximately 20 minutes until tender. Drain and peel the potatoes whilst still hot. Pass through a sieve. Mix the cream and butter, warm through, add to puree and mix thoroughly. Season to taste.
Assembling the Dish
Spoon the pomme puree into the centre of the plate.Sauté the pre blanched vegetables and mushrooms, season and deglaze with a little jus, spoon the vegetables around the puree, place the lamb saddle on top and pour a little jus around the plate.