FAVA BEANS APPEARED on the American culinary scene about twenty years ago, as farmers began to grow them not just as nitrogen-fixing cover crops but also for harvest, and chefs became infatuated with their bright green, right-from-the-garden flavor. I find the architecture of the plant astounding. I love to peel the puffy, fat pods to find those plump beans nestled in the cobwebby interior. Then those beans must be blanched in salted water for just 10 seconds before shocking in ice water. Only then do you get to slip off their pale green jackets and reveal the emeralds within.