Eggnog, standing rib roast, pan-browned potatoes, and rivers of gravy are just a few stars of the oh-so-heavy Christmas dinner. Which is why the Italian tradition of serving fish the night before is so appealing. It’s light, fresh and much of it can be made ahead and eaten at room temperature. Plus, you don’t need to be from the old country to serve it or wrestle with an octopus if your family isn’t into it. Think easy and premade, at least for the first few courses.