A trifle is not only one of the most elegant desserts around, it's also one of the most exuberant—which is why it is tempting to toss aside decorum and dive right into the bowl. The nontraditional version here is sturdy, made with robust gingerbread and mellow pumpkin mousse instead of the classic spongecake and custard.
Cooks' notes:
•Gingerbread (uncut) can be made 1 day ahead and kept in pan at cool room temperature (covered once cool).
•Trifle, without top layer of whipped cream, can be made 1 day ahead and chilled; whip half of cream just before serving.