Soak the cod in cold water for two days.
Put the peeled potatoes to boil. In another pan, bring to boil some water and add the cod.
Cook the cod between 9 and 11 minutes.
Slice the potatoes and arrange on a serving platter.
Cut the cod into pieces and place on top of the potatoes.
Melt the Bouquet - truffle butter in a saucepan and add the chopped parsley.
Cook briefly, until it amalgamates. Pour over the cod and serve immediately.