Shellfish and beans are a classic Italian combination. In the tradition of frugal and resourceful peasant cooking, nothing goes to waste in this dish. As the beans simmer away with the thyme, rosemary, and chile, they create another invaluable ingredient: a delicious stock. Starchy and flavorful, it’s added to the steaming shellfish, thickening their juices into a complex broth. The cavolo nero adds an earthy note and a chewy texture to the seafood stew. This is a rustic family meal in which everyone should take part, serving themselves from the bountiful platter at the center of the table. And don’t forget to serve big hunks of crusty bread for sopping up all those juices.
I like to use a wide pan, ideally 14 inches across, as opposed to a deep pan for this dish. That way all of the shellfish get coated and cook evenly. With a deeper pot, it’s difficult to stir, and inevitably some of the mussels and clams end up on the top