In Finnish we have “kissanristiäiset” (literally means a cat’s christening), which means some trivial and meaningless celebration/event.
I remember learning it as a semi-historical idiom, that nice white cakes and frostings could be expensive, so poor people would pay to have a pretty looking cake that’s mostly for show that’s like a prop or for a nice tasting cake that doesn’t look grand or large. Old guy could have been telling a tale though.