"Bigoli in salsa" is the traditional dish for days of fasting: Christmas Eve, Ash Wednesday and Good Friday.
Slice two large onions and clean 70g. of salted sardines or anchovies, washing them carefully and leaving them to soak for a while. Lightly fry the onions and the sardines, cut to pieces, in 100 ml. of olive oil, first over high flame without a lid and then, when the onions turn golden, add two spoonfuls of water to halt the cooking, cover and leave over a very low fire until the onions are completely soft like tender golden fillets. Cook 400 g of pasta until it is "al dente" and season with the sauce, adding a pinch of freshly milled pepper. There are many variations of this dish whose traditional recipe is the one here: you can add garlic, or use tuna fish instead of the sardines.