Pierogi (pyeh-rroh-ghee) are Polish filled dumplings. You will always see the word in this plural form and not in its singular form -- pieróg.
Dumplings are like people. They come in all shapes, sizes and ethnic origins. Russians have their pelmeni and piroshki, Ukrainians call them varenyky, Jews have their kreplach and knishes, the Chinese have their potstickers and wontons, and Italians have ravioli. In fact, horror of horrors, many Americans refer to pierogi as Polish ravioli.
Beyond providing sustenance, their sole purpose in life seems to be to give the tummy a big hug, like a pat on the hand from mom when you're having a bad day. "That's all right dear, things will get better."
Filled dumplings came to Poland in the 13th century from the Far East via Russia. They didn't appear in their present form and weren't called pierogi until the second half of the 17th century. Because they took a fair amount of work, they were prepared only during holidays. With each holiday came a different type of pieróg, unique in its filling and shape. Kurniki are large wedding pierogi always filled with minced chicken. Knysze or "mourning pierogi" are typically served after a funeral. Sanieżki and socznie are sweet little pierogi fried and served on the occasion of imienimy or one's name day. Tiny versions of pierogi are known as uszka or "little ears."
The most traditional fillings for pierogi include minced cooked meat, sauerkraut with mushrooms, seasonal fruits like blueberries and strawberries, buckwheat or millet, savory or sweet-savory curd cheese, and potato-onion-cheese (Pierogi Ruskie). Nowadays, spinach, seafood, and other "gourmet" pierogi are seen at Kraków's Pierogi Festival held annually in August.
In the United States, many church groups make them on Fridays year-round as fundraisers. If you can't avail yourselves of such a church group in your area, know that homemade pierogi aren't as difficult to make as you might think. Pierogi dough is rolled to a 1/8-inch thickness, cut with a 3-inch round, filled, folded over, sealed and crimped, and boiled. Some people serve them with melted butter right out of the boiling pot. Others prefer to fry theirs after boiling until they are slightly crispy.
It's a fun rainy-day project and terrific to do with the kids or grandkids, especially if done in steps. Make the dough one day, roll and fill another day, and cook yet another day.
There's no right or wrong on the fillings, so you'll see everything from blueberry to sauerkraut and mushrooms. Serve sweet pierogi with confectioners' sugar, and savory pierogi with, bacon bits or pork cracklings known as skwarki and sour cream, if desired.