Cut the shallot into strips and bring to the boil with the white wine and Noilly Prat. Add the fish stock and reduce all the liquid to a third. Then add the whipped cream and carefully make 3-4 minutes.
Later, mix the potato starch with a little bit of water until smooth and thicken the fish sauce with a few drops.
Mix accurately with the whipped cream. Season with salt, pepper and juice of one lemon.