Poach the darne in salt water.

Dish up by surrounding the darne with medium-seized mushrooms stewed in butter and garnished with shrimps and a few tablespoonfuls of Nantua sauce; a small round quenelles of mousseline forcemeat for fish, decorated with truffles, and some slices of milt treated à l'Anglaise, and fried when about to dish up. Serve Nantua sauce separately.