Normandy fish stew
This fish stew from northern France, sometimes called Marmite Dieppoise, is a great comfort food meal
Melt the butter in a large saucepan, add the onion and cook for 3 mins. Tip in the fish heads and bones and cook, stirring occasionally for a further 4 mins. Pour in the wine and 1 litre of cold water. Drop in the herbs and a pinch of salt. Bring to the boil, reduce the heat to a simmer, then cook for 20 mins, skimming when needed. Pass through a sieve and use for your intended recipe. Will keep in the fridge for a week and for three months in the freezer.