Nocino is a pleasantly bitter liqueur made from green walnuts, spices, and lemon. In the Mediterranean, it's usually made around the end of July. I hear tell it coincides with the Feast of San Giovanni in Italy. It can be a bit of an acquired taste, though, and the dessert chef David Lebovitz suggested introducing people to it through a custard. Great idea, I thought, but I wasn't in the mood to fuss with eggs and water baths, so I went a simpler route. This stove top version is thick and luscious, and would be good flavored with any liqueur.