By Gary Rhodes
This is one of the simplest possible sauces, which has a silky texture and just enough acidity for the Salmon Fish Cakes. It goes well with cod, too.
Chop the butter into 1 cm (½ in) pieces and put into a pan with the lemon juice and chicken stock. Bring to the simmer, whisking all the time. Do not allow the sauce to boil or the butter will separate. If