Never heard of those "bitterbollen" things. We do, however, have something similar for dinner on the 24th (on the evening of which, after church, the matter of presents is dealt with) every year: pastries made of what the Google translator calls "sheet paste" (I don't have a real dictionary handy, unfortunately) with a sauce consisting mostly of champignons and carrots, plus cranberries, plus Worcestershire sauce. We generally buy our stollen and gingerbread, but make assorted types of biscuits ourselves, usually cinnamon stars, lemon hearts, butter cookies and another sort that I doubt is called "pepper nuts" in English, although that would be the direct translation of the German name.
On Christmas Day, there's duck (except for me, the vegetarian), red cabbage (except for me, who does not like it) and croquets (The potato things. I hope that's the correct word. Unlike the rest, I eat them). The following days consist mostly of eating what remains of this.
Oh, and please allow me to shout MARZIPAN.

Fuzz"it's intriguing how the most interesting Christmas traditions are the ones about food"pilz