Kinda similar to Fizzandchips, my job has always been peeling a mountain of potatoes and veg for Christmas dinner the following day (Mum entertained the cleaner for her Christmas drink and a gossip by the fire, Dad took the other 5 DCs shopping and for lunch in the city an hour away). I still do that for our own Christmas dinner if we are cooking at home ourselves - but DH works with me and DD makes cookies for Santa (and sometimes actually helps). The cookies are sometimes made from scratch, but just in case we don’t have enough time or energy, I always keep a half batch of dough from baking earlier in December and freeze them, to just slice and bake on 24th.
After a buffet type of dinner, We also do another of my family’s traditions, with the youngest lighting the Christmas candle (traditionally placed in the window to show any weary travellers that there is room in our Inn to shelter them- we have always put ours on the mantelpiece). We take a few minutes as a family to remember the year just finishing, the good and bad things, and to think about family no longer with us, and say a short prayer of thankfulness together for what we have.
Then we combine a tradition from DH’s family (new pjs on 24th) and MN CEH - which holds DDs plastic Santa plate and glass and her stocking as well as pjs, bath bomb and nice hot choc for all, and a Christmas craft beer for DH. Dd lays out stocking, milk and freshly baked cookies, has her batch, comes down for hot choc and a cookie, and then I read “‘Twas the night before Christmas” to her in bed.