Re:NY City's Onion Sauce
As I read your post, I immediately thought "Oh, yeah, that gloppy stuff!"
and wondered: "Hey is that just a NY thing???"
and read the article and found out yes, it is.
But I have a bone to pick - I have seen Black & White Cookies in other cities, (and countries, including Germany, where it is sold in bakeries as an "American". )
(now also to our onion hot dog sauce on wursts in Germany - well ???)