Never heard of them either. We true Irish-Americans pride ourselves on unsophisticated palates! (first generation meself) My mom got off the boat in Boston and went straight to Ohio, so I guess she missed the Philadelphia area treat.
I’m from Philly and grew up with the homemade ones. I have to google every year for the recipe if I make them now. But a little tip if the recipe doesn’t mention it is to pulse the coconut in your food processor before mixing it in.
It gives the center a nicer texture.