Pierogi

Potato/cheese filling:
1 tbsp grated onion
2 tbsp butter
2 c. cold mashed potatoes
1/2 c. shredded cheddar cheese
4 oz. cream cheese
salt and pepper
Saute onion in butter until tender, combine with potatoes and cheese, season to taste.

Sauerkraut filling:
1 lb. sauerkraut, rinsed
1/2 onion, diced
1/4 lb. bacon, crispy, in pieces
salt and pepper
Saute (do not stir too much or it'll never brown).

Prune filling:
2 c. dry cottage cheese
2 tbsp sugar
2 tbsp melted butter
6 tbsp chopped prunes
salt
2 egg yolks
cinnamon
Combine.

Pierogi dough:
2 1/2 c. flour
1/2 tsp salt
1 egg
2 tsp vegetable oil
3/4 c. warm water
bacon, crisp, chopped (optional)
onion, chopped, lightly browned in butter (optional)

Mix flour with salt in a deep bowl. Add egg, oil, water to make a medium soft dough. Knead on a floured board until smooth (not too much, though, or it'll toughen).
Divide dough into 2 parts, cover, let stand for at least 10 minutes.
Roll dough thin on a floured board. Cut rounds with a biscuit cutter or the open end of a glass. Put a spoonful of filling in it, form a half circle, press edges together with fingers, make sure it seals well.
Place pierogi on a floured board, cover with a tea towel to prevent from drying out. Drop a few (not too many) into a pot of boiling salted water. Boil 3-4 minutes. They'll be ready when they're puffed. Remove with a perforated spoon or skimmer, drain thoroughly.
Place in a deep dish, sprinkle with melted butter, keep them hot. Don't pile/crowd them.

Source: Chef S. Culp, PA Culinary Institute, Polish Enthusiast course, 11/6/07