Pierogies are similar to goyza, but filled with potato and slathered in butter. You can really do any variety as well, sauerkraut, cheese/potato, broccoli/potato, and sweet cheese are all pretty common. But again, there are all kinds of variations. I would say Pittsburgh-Cleveland-Chicago is probably the Pierogi belt in the States, due to the Polish/Ukrainian immigrants that settled there. Old ladies at Orthodox or Catholic churches make the best!
