Polish Cheese and Potato Pierogi

Description
A pierogie is a Polish dumpling. It is typically made of dough and a filling. The dough is usually made of flour, water, salt, and egg, and is made into small circlets and filled with things like potato and onion or cheese, cream cheese, fruits, etc. The dough is then folded in half and the edges are crimped, so the pierogie is in the shape of a half moon. The pierogie are then boiled in salted water until they float. They may also be pan fried with butter.
 * Contributed by: Zwolak, 2008

Pierogi dough

 * 2 cups sifted flour
 * 1 egg
 * ½ cup lukewarm water
 * 1 teaspoon salt
 * 2 tablespoons melted butter

Pierogi filling

 * 1 to 1½ pounds farmer's cheese, or dry plain curd cottage cheese
 * 2 to 3 potatoes, peeled, boiled, and mashed.
 * salt and pepper to taste.

Directions

 * 1) Mix all dough ingredients in a large bowl with a spoon and knead lightly in the bowl.
 * 2) Rest dough for one-half hour covered with a kitchen towel or plastic wrap.
 * 3) Mix the filling ingredients mix in salt and pepper to taste.
 * 4) After one-half hour, knead the dough a few times on a floured surface and roll out to ⅛-inch thickness.
 * 5) Cut out with a 2½-inch to 3-inch wide round cookie cutter or drinking glass (dip cutter or glass in flour to keep dough from sticking).
 * 6) Place a teaspoon full of filling in the middle of each dough circle (when you become an expert, add a little more filling for a plumper pierogi).
 * 7) With floured hands, fold the dough over the filling, and, starting at one end of the resulting crescent, pinch the dough together to enclose the filling.
 * 8) As you pinch the dough closed, continuously work the filling into the pierogi with floured fingers.
 * 9) Make sure the pierogi dough is tightly sealed, or these little dumplings will come apart when boiled.