Or, more accurately : Pączek. Pronounce it halfway between "Pon-chek" and "Pawn-chek". The funny cedilla-type accent under the a, modifies it to a long "a" and adds an 'N' sound.
A sweet snackette that is popular in Poland.
Despite, the Polish ~ek ending being a diminutive, a pączek is a large yeast doughnut, deep fried and filled with a fruit jelly, or jam, then covered in icing sugar. Usually they are spherical in form, and three to four inches in diameter (somewhere around 7 to 10 cm). The outer skin is brown, having been cooked in the deep fat.
The word is more often heard in the plural: Pączki. Again, the "a" has been modified, so it sounds like a cross between "Ponch-ki" and "Pawnch-ki".
Pączki are, in a word, delicious, which probably explains why the singular form of the word is rarely heard--you tend to want more than one of the things.
They are traditionally eaten on the Thursday before Ash Wednesday, which the Poles call Fat Thursday. While you may think this date refers to an expanding waistline, due to the large number of sugary doughnuts consumed, the derivation is closer to the French Mardi Gras (fat Tuesday).
On a more personal note, the first Polish sentence I ever used in Poland was this:
"Sześć pączki, prosze, Pani" ("Six doughnuts, please, madam")
For a recipe (I have not tested it) look under Yeast Doughnut.