butter or oil 50 g
onions, sliced 200 g
white fish bones (preferably sole, whiting or turbot) 2 kg
lemon, juice of
peppercorns 8
bay leaf 1
parsley stalks
water : 4.5 litres

Melt the butter, or heat the oil, in a thick-bottomed pan.
2 Add the onions, the well-washed fish bones and the remainder of the
ingredients except the water.
3 Cover with greaseproof paper and a lid; sweat (cook gently without
colouring) for 5 minutes.
4 Add the water, bring to the boil, skim and simmer for 20 minutes, then
strain. A longer cooking time will spoil the flavour.