This is the salted and sundried roe of grey mullet and tuna: it can be obtained from italian speciality shops in the piece or in tins.
(Tuna fish bottarga is less delicate in flavour.) The best bottarga is that which is removed immediately from the fresh fish membrane intact then pressedsalted and dried in the sun. The best is found in the market in Caligari Sardinia firm and moist just right to grate.
Spaghetti with mullet bottarga, olive oil and chilli flakes is to be seen on the menu of every restaurant in Sardinia.
A salad of finely shaved bottarga with raw fennel lemon juice and olive oil is a favourite.