"I love cooking the hell out of leeks," Jerry Traunfeld says. "They get this melty, rich quality and saucy consistency." In this luscious dish, he combines the slow-cooked leeks with meaty porcini mushrooms and cranberry beans (a.k.a. borlotti or shell beans), which can be found fresh in early autumn and taste like chestnuts. The dish can easily be adapted for carnivores by adding bits of crispy bacon or that key cassoulet ingredient, duck confit.