In Mimi Sheraton’s book “The Bialy Eaters,” from 2000, she entertains, and soundly dismisses, a theory that the bialy, a bagel-adjacent Jewish roll, originated not in Bialystok, Poland, but in New York. Bialys—which are not boiled before they’re baked; which have shallow depressions at their centers instead of holes, to be filled with onions and poppy seeds, most traditionally; and which bear a dusting of white flour—may not have been invented here, but is there any city in the world where it’s easier to find them? In the nineties, on a trip to Bialystok, Sheraton failed to locate a single bialy. In 2022, Kossar’s, New York’s most enduring bialy bakery, which opened on the Lower East Side almost a century ago, is expanding. In July, a second shop débuted on…