Cavatelli are gnocchi-shaped pasta but with a hollow centre - hence the name cavatelli, which means "little excavations." If you do not want to invest the time to make them fresh, you can buy them prepared, dry or fresh, from a pasta shop. But if you do make them, you can enhance the flavour with simple additions to the basic recipe, such as, in this case, cocoa powder, which makes the dish more interesting. If you're game, your local Italian supermarket or kitchen store should carry a cavatelli maker, a great little tool. Buon appetito!