Pierogi are filled dumplings of Central and Eastern European origin, made by wrapping unleavened dough around a savory or sweet filling and cooking in boiling water, or pan-frying.

Pierogi which consist of noodle dough and have to be cooked in boiling water are associated with the Central and Eastern European kitchens where they are considered national dishes, especially in Poland.

Pierogi-like dumplings are popular in most Central and Eastern European countries as well as in Ashkenazi Jewish and modern-day American cuisines, where they are known under their local names.

The dumplings may be served with a topping, such as melted butter, sour cream or fried onion, or a combination of those ingredients.

Pierogi may be stuffed with mashed potatoes, fried onions, cheese, cabbage, sauerkraut, meat, mushrooms, spinach, cheese, or other ingredients depending on the cook's preferences.

Dessert versions of the dumpling can be stuffed with a fresh fruit filling such as cherry, strawberry, raspberry, blueberry, apple or plum, as well as jam. For more flavour, sour cream can be added to the dough mixture, and this tends to lighten the dough.

Unlike other countries with newer populations of European settlers, the modern pierogi is found in a wide selection of flavors throughout grocery stores in the USA and Europe.

More Info: en.wikipedia.org