Quince is the most luscious fall fruit, but not as widely known or easily found as it should be. It holds its secrets tightly inside; quince is very astringent and not pleasant to eat when raw, but when cooked with sugar it turns coral-pink and delicious. It's also very high in pectin, which means that it is practically perfect for sorbet. This fragrant sorbet, spiced with star anise and vanilla, is thick and smooth — more like a sherbet than an icy sorbet — and it makes a wonderful accompaniment to autumn gingerbread and apple cake.