Forget the gingerbread house. Your holiday dessert should be simple to prepare, so you can spend more time with your family (that is what Christmas is about, right?). Here's a quick chocoalte mousse recipe from Nigella Lawson's cookbook,
Nigella Express: 130 Recipes for Good Food, Fast.
Nigella says that most mousses need to be made the day before, to allow the egg yolk to set. Here's her "instant" ...