1 cup (8 ounces) cream style cottage cheese, drained
1 egg yolk, beaten
1 tablespoon butter, melted
1 teaspoon sugar
1/4 teaspoon salt
2 1/4 cups flour
1/2 teaspoon salt
2 tablespoons butter, cut in pieces
1 large egg, at room temperature
1 egg yolk, at room temperature
1/2 cup reduced fat milk, at room temperature
2 tablespoons sour cream, at room temperature
Combine all ingredients and refrigerate until ready to assemble pierogi.
Combine flour, salt and butter in food processor fitted with a plastic blade. In a separate bowl, blend together egg, egg yolk, milk and sour cream. Add to flour mixture and process until dough cleans sides of bowl and sticks together (it will be slightly sticky). Remove, shape into a ball, wrap in plastic and chill 3 hours or overnight.
Cut dough into thirds; roll each section out on floured surface into 12 inch round. Cut each round into eight 3 inch dough circles. Moisten outer edges of each dough circle with water; place 2 teaspoons filling on each and fold dough over. Seal edges by pressing gently with the back of a fork.
In large pot, bring 12 cups salted water to boil. Add 12 pierogi at a time, reducing heat to a gentle boil; cook 5 minutes, or until pierogi float to the surface. Remove with a slotted spoon, drain on paper towel and transfer to serving dish. Repeat with remaining pierogi. Serve warm topped with sour cream and onions sautéed in butter until golden brown.