The trick with dessert, whether you're serving dense, sticky plum pudding, cream-laden trifle or something light and fruity, is to partner it with wine that is as sweet. Anything less sweet will taste thin. Botrytis, the mould that sweetens and intensifies the flavours of many sweet whites (not just Sauternes), is a boost for almost all desserts. Acidity is critical too. Without enough of it the wine can taste flabby and flat.