It's very simple, but a bit time consuming (which is the whole point of getting together and doing it).The filling is just mashed potato with whatever you want in it. I like cheese and onion.
The dough is super easy:
5 cups of flour
2 cups of water
1 teaspoon of saltWe used about 2lbs of potatoes for the mash, and made up 3 batches of dough to make about 140 pierogies.Mix it all together until it's a dough and divide it in half. Keep one half covered and then roll out the other half and use a glass or a cookie cutter to make the circles. Put in the filling and then fold over and pinch the edges together really well. Pressing the edges together well is really important, otherwise they will bust open when you boil them and the filling will leak out.
As you make them lay them out on a tray and then freeze them. Once they are frozen solid bag them up about 6 per bag, they will be easy to make for a quick dinner or snack. To cook: Boil them for about 6 mins or until they have risen to the top of the pot then remove them with a slotted spoon and fry in a bit of butter until browned on the outside. You can eat them with sour cream, or whatever really. A side of sauteed onions, or even some ketchup!