This is long shot but why not, here is the song, which is insanely catchy, and I learned it way back when in high school German class, and I like to sing it around the house, but seriously I know nothing about it. Who wrote it? Why a song about steamed buns? Is it really a folksong, because it's a novelty song about steamed buns, and I don't know if that is normal for folksongs. A song that has puzzled me as long as I have known about its existence.
That's quite the coincidence... Yesterday or the day before they brought that song on Deutschlandfunk (public radio). It isn't in their archives (for copyright reasons), but the composer was apparently Franz Xaver Engelhardt - German wiki only I'm afraid, church musician and composer. His name also brought me to a shop selling these notes to the Dampfnudel-song and another one titled the Wurst-song. G. Eberl is credited with the lyrics, but I have no idea who he is and no other leads. I know not much about German music history, but such humoristic songs about mundane topics seem to me to have been pretty popular around the turn of the century. Maybe that info helps a bit.