In the rugged landscape of northern Tuscany, where the mountain air is crisp and most villagers work out-of-doors, soup never comes from a can. Homemade and hearty, soup-zuppa-is the meal of choice, and each household harbors its own family secrets for preparing the traditional recipes of the region. Here are one-dish meals to inspire the most harried or jaded cook-from zuppa alla povera con erbe di prato (a "poor people's soup" of fresh greens...