Eye Fillet with Madeira Sauce and Caramelised Sweetbreads

To prepare the beef fillets, remove any sinew or membrane and slice fillets into 5 cm heights. To cook the beef fillets, pre-heat oven to 230 degrees. Ensure you season fillets all over with salt & pepper. Heat an ovenproof frying pan with olive oil & clarified butter until hot and sear the fillets all over to colour. Place beef fillet on buttered baking paper and place in the oven to cook for 6 minutes for rare or 8 minutes for medium-rare. Make sure you turn over at the halfway point. Then remove from oven and leave to rest for 5 minutes.
 
To prepare sweetbreads, place them in a bowl of milk. Rest for 20 minutes. Rinse sweetbreads under cold water and make sure they are clear of blood. Place sweetbreads and remaining ingredients in to a saucepan and only just cover with water. Bring the saucepan to a simmer and cook the sweetbreads for 4 minutes. Drain and allow cooling. Carefully peel off any membrane, dip sweetbreads in brine solution and place on tray, cover with cling film wrap and place a second tray on top. Add weight on top to press down and place in fridge for 1 hour.
 
When you are ready to cook sweetbreads heat the Madeira sauce, remove the sweetbreads from fridge, heat a large frying pan with olive oil and a tablespoon of butter and when hot, add the sweetbreads to brown about 40 seconds. Add 50 mL of Madeira sauce and reduce to a glaze, coating the sweetbreads as it reduces. Remove sweetbreads from the pan. 

Place the potatoes in a pot of salted water. Bring to a boil gently until the potatoes are tender and there is no resistance when you poke with a knife. Drain the potatoes and return to the empty pot over medium heat for a minute to steam off excess moisture.
 
To finish the potato puree, it's extremely important that you re-heat with a low temperature when adding butter and cream as this will ensure the best emulsification. If the heat is too high the potatoes will become oily. Peel the hot potatoes, pass through a drum sieve and place the puree in a heavy pot. Add salt & pepper and beat with a wooden spoon, then gradually add butter & cream. Keep adding butter & cream until you reach the desired texture. Rinse pikopiko with cold water.
 
Heat butter in a heavy-based saucepan and, when hot, add beef trimmings and cook until nicely browned. Add shallots and garlic and cook for about five minutes until soft. Add mushroom, thyme and peppercorns and cook until all the moisture the mushroom produce has evaporated. Add sherry vinegar and completely reduce. Add Madeira and reduce to a syrup over a high heat. Add beef stock and chicken stock and simmer for 30 minutes, skimming off any impurities that rise to the surface. Pass sauce through a fine sieve and then through a muzzle cloth to remove any sediment. Allow to cool. Once cooled, store in fridge.