Pierogi ( also spelled perogi, pierogy, perogy, pierógi, pyrohy, pirogi, pyrogie, or pyrogy in English or other Slavic languages juvenile diminutive form Pierożki also in use) are dumplings of unleavened doughfirst boiled, at which point they can be served with melted butter or various toppings, or then fried with onionstraditionally stuffed with potato filling, sauerkraut, ground meat, cheese, or fruit.