There are a lot of traditional Christmas food served on Christmas day and the day after (since it’s still a holiday for us) but it depends on where you live.
Everywhere, anyway, the most traditional food is the Panettone and for us who don’t like candied fruits, the Pandoro.
Where I’m from, Lombardy, staffed capon is the main dish even if we, as family, don’t have it.
Moreover, there are families who celebrate and have a big Christmas Eve dinner (usually fish based), and families who celebrate on Christmas day, but anyway both have hors d’oeuvre, first course, second, cheese, fruit and dessert.