Although this recipe appeared in a Larder column several years ago, I heard that several people had loved it but lost it, so here it is again. Choose a plain or fancy fluted mold of two-quart capacity (or a bundt cake pan). Oil it lightly and chill it before you start. Another advantage of this dessert is that it can, and should be, made at least 24 hours in advance — even two days is fine. The flavor and firmness develop and the mousse is easier to unmold after this time. Unmolded before dinner, covered with plastic wrap, and replaced in the refrigerator, this is a fairly carefree finale to dinner. Serve with clouds of real whipped cream only barely sweetened.