Slice the fish into 12 even sized medallions and marinate.
To make the base for the eggwhite sauce bring the chicken stock to the boil and thicken with wheat starch, season with salt, pepper and soy, set aside.
In a deep fryer or wok heat oil to 160° Celsius and fry pasta until it is crisp, then cool the oil to 140°Celsius.
Heat a little vegetable oil in a pan and season with sea salt. Fry 2 cloves of chopped garlic then add in baby cos which has been cut into quarters, add asparagus and a little water, put a lid on and steam vegetables until tender, stir in duck confit and keep warm.
Poach the fish in the oil until just cooked, remove and drain on absorbent paper, keep warm.
Bring the sauce back to the boil and gently stir in crab meat, trying not to break it up too much. Lightly whisk the eggwhite with a fork and add to the sauce, do not over cook the eggwhite or the sauce will not cling. Correct the seasoning if necessary and finish with the chopped spring onion and chervil.
To assemble the dish arrange the pasta on the plate, then the cos and asparagus making a platform for the fish, sprinkle with the duck confit and spoon over the sauce, garnish with a fresh sprig of chervil.