Polish/Ukrainian

Beat the first 4 ingredients. Mix in the flour, adding more flour if necessary., until the dough forms a soft ball. Divide dough in half. On a floured board, roll each half of the dough into a thin sheet. Cut circles in the dough with a cutter 3 1/2 -4 inches in diameter.

Cheese filling: Cream yolks and butter. Combine with other ingredients and mix. Put 1 teaspoon of filling on each dough circle, being careful to place it off center. Moisten the rim of the circle with water. Fold the unfilled side of the circle over the filling and press the edges of the resulting crescent firmly to seal them. Drop the pierogi into boiling salted water. Cook gently for 5 minutes. Remove with perforated spoon. Serve with melted butter and sauteed onions.

when crowded or piled, cooked pierogi become misshapen and heavy