Anyone have any suggestions? We're having a family Xmas get-together in a rental house. We'll be leaving our house early Xmas Eve (as in, still dark outside), so whatever I decide on needs to be made by the night before that (the 23rd). We're responsible for dinner (and dessert) on Boxing Day (the 26th), so it still has to be good by then. And it has to survive 12 hours in the car (so nothing frozen or crucial refrigeration - we'll be taking a cooler, so it could be kept cool but not cold).
In case it matters, dinner will be chili and cornbread. I really don't want to be spending a ton of time in the kitchen on my vacation, so I really want dessert to be ready to go for the most part (assembly required okay).
ETA - 11 adults and 2 toddlers.