Quick and easy to make fish stock is essential if you are going to do anything other than just plain grill your fish. Although the stock can be made from any fish bones the best ones to use would be those of flat fish, monkfish and possibly whiting. Once made it will keep in a refrigerator for up to 5 days but can always be frozen, freeze it down into usable quantities and defrost as and when you need it.
Salmon, cod, haddock bones do not make a good stock.
About 1lt/1¾pts
450g/1lb fish bones
900g/2lb white vegetables (white of leek, celery, onion, fennel)
45ml/1½floz olive oil
85g/3oz mushrooms
150ml/5floz dry white wine
½ lemon
bouquet garni of parsley, or parsley stalks, thyme and bay leaf
1 tbsp white peppercorns
Remove any blood from the bones and, if using the heads, remove the gills. Wash the bones really well in a few changes of cold water. Peel and wash the vegetables and roughly chop them. Heat the oil in a saucepan, add the vegetables and mushrooms and sweat for a few minutes until the vegetables start to soften and with the pan covered. Add the white wine and reduce slightly. Cut the lemon into two and add to the pan with sufficient water to just cover the bones. Bring to the boil and skim frequently. Once it reaches the boil reduce it to a simmer. When no more scum comes to the surface, after about 5 minutes, then add the bouquet garni and the peppercorns then simmer for 20 minutes. After 20 minutes strain the stock through muslin or fine cloth and allow to cool.
There is no point in cooking the stock for more than 20 minutes, as no more flavour will be extracted from the bones after this time. If the stock is not very strong then reduce it to the desired level after straining and for storage. It freezes well.