OAKMONT, Pennsylvania — Forty years ago, Marc Serrao started making paczki. Serrao had just started his modest bakery in the suburban Pittsburgh river town when he decided to try his hand at the doughy confection, pronounced poonch-kee, which is filled with rich white sweet creams or candied jam fruits and traditionally made by Polish bakeries on Shrove, or Fat Tuesday.

“I made a batch of them for Fat Tuesday that year, which was three dozen,” Serrao said. “And I was so excited with how they turned out that I called my wife and told her not only how good they were but how they sold out that day.”