In my experience a Bulgarian Christmas is family, food, and snow — all in large portions. To be fair, minus the snow, that pretty much describes any time of year in Bulgaria! Allow me to elaborate (and share a few specifics)…
Food
For the purposes of this list family and food are one in the same; recipes and traditions about food are passed down from generation to generation, and food is enjoyed together.
Apparently, according to traditions in Eastern Orthodox Christianity, people are supposed to forgo animal products like meat, eggs, milk, cheese, etc for forty days before Christmas. In practice (and probably more so in urban areas) it seems like people generally only do this on Christmas eve.