Rinse the broad beans and soak for 24 hours in a bowl with plenty of cold water. Once drained shell and rinse them under running water.Put the broad beans in a large saucepan, add the bay leaf, peel, wash and chop the onion and toss into the same pan; then cover this batch of vegetables with plenty of cold water.Bring to the boil slowly, add a pinch of salt and simmer covered over a medium heat for about an hour. In the meanwhile, peel the potato rinse it and cut it into chunks.Fifteen minutes before the broad beans are ready add the potato and finish cooking. Pass this mix in a vegetable mill and put it into the pan again.Cook the pasta in plenty of boiling salted water. Drain it well al dente and mix it with the broad-bean mash.Bring it to the boil again and simmer for a few more minutes, stirring often with a wooden spoon.When it is ready remove the pan from the heat, sprinkle with the oil and with a grind of pepper. Stir and pour the maccu" in the serving dish. Serve it both warm or cool to taste."