Pierogi are a kind of dumpling also known as perogi, perogy, piroghi, pirogi, or pyrohy. Most English-speakers treat these forms as singular and form the plural by adding -s, but a few consider them plural and form the singular by removal of the -i or -y. In Swedish however, the singular form is pirog and the plural form is created by adding -er at the end. Pierogi is the plural form of the Polish pieróg. The word itself comes from the Old Slavic "pir" (festivity).
Pierogi are of virtually untraceable Central or Eastern European origin; claims have been staked by the Poles, Romanians, Russians, Lithuanians, Ukrainians, Slovaks and Rusyns. Similarity to dumplings found in the Far East such as Chinese potstickers fuels speculation, well-founded or not, that the Mongols and Tatars brought the recipe to the West.
Pierogi are semi-circular dumplings of unleavened dough, stuffed with sauerkraut, twaróg, mashed potatoes, cabbage, onion, meat, hard-boiled eggs (the last is rather Mennonite-specific), or any combination thereof, or with a fruit filling.
They are typically fried, deep-fried or boiled until they float, and then covered with butter or oil; alternatives include the Mennonite tradition of baking and serving with borscht, and the Polish way of boiling, then frying in butter. They are typically served with plenty of sour cream, and the savoury ones are topped with fried bacon or onions. The most popular of the Polish variety are savoury pierogi ruskie, stuffed with farmer's (aka dry cottage) cheese, mashed potatoes, and onion. Varenyky or vareniki (from varyt', "to boil") are the Russian or Ukrainian version of pierogi. One variation of the pierogi are the meat-filled, boiled dumplings called pelmeni (пельмени), originating in Siberia, are very popular throughout Russia and in other parts of the former Soviet Union.
USA and Canada
In the United States, the term Pierogi is commonly taken to mean Polish pierogi.The pirog (or its equivalent in the various Slavic languages) means pie, which can take the form of a stuffed dumpling, pastry, or two-crusted pie. In Russian, pirogi is the plural form of the generic pirog, which usually refers to a large double-crust pie and not a dumpling (pelmeni or vareniki) or filled bun (pirozhki).
By the 1960s, pierogi were a common supermarket item in the frozen food aisles in parts of the United States and Canada. Pierogis maintain their place in the grocery aisles to this day.
Many of these grocery brand pierogis contain non-native ingredients to appeal to general American tastes. Products Mrs. T's Potato, Cheddar, and Jalepeno pierogi  and Trader Joe's Potato Cheddar or Chicken Pierogi.
The Canadian Prairies in particular have a large Ukrainian population, and pierogi (usually called perogy, -ogies [pəˈroːgi]) are very common in restaurants and supermarkets, and so familiar that some Asian restaurants bill their pot-stickers as "Chinese perogies". Ukrainian-speakers call them pyrohy, which can be misheard pedaheh by anglophones unaccustomed to the fast rolled-r sound, or alveolar tap.
Packed frozen pierogi can be found everywhere Russian or Polish communities exist. Such pierogi are made by industrial machines, often built by Italian companies such as Arienti & Cattaneo, Ima, Ostoni, Zamboni, etc. These pierogi usually weigh around 20 grams each but resemble an oversize half-moon ravioli, since the aforementioned Italian pasta machines are commonly used for industrial production.
In 1993, the village of Glendon, Alberta, Canada, unveiled its roadside tribute to this culinary treat: a 25-foot (7.6 m) perogy, complete with fork.
In Russian cuisine, pirozhki (also piroshki, or Ukrainian pyrizhky) are small stuffed buns made of either yeast dough or short pastry. They are filled with one of many different fillings, and either baked or fried. The singular form is pirozhok, the diminutive form of the word pirog. The stress in pirozhki is properly placed on the last syllable: [piroʒˈki].
In Hungarian cuisine, the pierogi is used as primarily as a festive food for special occasions such as weddings. It was brought to Hungary by the merchant Andras Perl for his wedding with his wife Katalin in 1764. The Banki family, home to Katalin, usually renowned for its ferocity in battle, was so moved by the pierogi that now, pierogi are common at most Hungarian weddings.
Pierogi are popular throughout Russia, Central Europe, and Eastern Europe, including Ukraine and Poland, and in areas of North America where immigrants brought their cuisine. Pierogi at first were a family food among immigrants, but in the post-World War II era, freshly cooked pierogi became a staple of fundraisers by ethnic churches.
Pierogi. (2007, March 8). In Wikipedia, The Free Encyclopedia. Retrieved 03:15, March 13, 2007, from http://en.wikipedia.org/w/index.php?title=Pierogi&oldid=113534848