For Maggie's birthday, I made a sweet potato cake...took a sweet potato, nuked it and squashed it up with a little butter and added some cooked broccoli and shaped it into a little mound.
If you go to the health and diet forum, there is a thread for recipes. I can say that they had some treats made from the list (person's name was pillar or something like that) they LOVED those treats. I guess you could make a little cake with it.
Good luck and Happy Birthday to the both of you! That's cool that you share a birthday!