Fish stock makes seafood-based chowders, pastas and risottos sing. Ask your fishmonger for heads and bones from white fish only. (Salmon bones have a bitter, almost musty taste.) Save yourself some time by having him chop them, too. Don’t be afraid to use fish heads; they give stock a rich layer of flavour. One more tip: Don’t simmer for longer than 30 min or stock will taste strong and bitter.