One wintry night in February several years ago, at Guy Savoy's restaurant in Paris, Patricia Wells was introduced to this sublime soup. It combines the nutty flavor of artichokes, the richness of Parmesan and the fragrance of fresh black truffles. This is a home version, so she has omitted the costly truffles. Although she prefers to prepare this with fresh artichokes, Wells is aware that many cooks may not have the patience for turning artichoke bottoms. She has tried this recipe with artichokes in a jar and finds the flavor too dull. However, frozen artichokes--usually sold in nine-ounce packages labeled artichoke hearts--are a worthy substitute. The wine here works its magic, adding just enough acid to lighten the soup.