Gorgonzola is Italy's great blue cheese — a cow's-milk cheese from Lombardy and Piedmont, its ivory paste marbled with blue-green veins of Penicillium mould. It comes in two faces: dolce, young and pale, soft and spreadable with a sweet, milky tang, and piccante, aged firmer and crumblier, with a sharp, salty, decidedly pungent bite. Either way it carries the bittersweet, faintly metallic prickle of blue mould, and either way it melts readily, collapsing into sauces, risottos and polenta or softening over warm bread.