PREPARE FILLING: Drain 1 (16 oz.) can sauerkraut, then fry in 1 stick of butter until light brown. Peel and boil 8 pounds of potatoes; drain well. Cubed 1 1/2 pounds of Velveeta cheese. Mix all ingredients in large bowl, while sauerkraut and potatoes are still piping hot. Set aside.

DOUGH: In very large mixing bowl, beat 4 eggs, 2 cups water, 2/3 stick butter, and a pinch of salt. Gradually add 6 cups of flour (may need more to achieve soft texture). Knead dough on generously floured surface until air bubbles out and dough is soft and pliable, not sticky.

Using 1/4 of dough at a time, roll to 1/8 inch thickness on floured surface. Cut large circle sin dough (3 to 4 inch cutter). Place a heaping teaspoon of filling in center of each circle. Fold over and pinch seam closed. Use fork tines dipped in flour to flute each seam. Repeat until all dough and filling is used up.

Boil Pierogi's in large pots of water with small amount of oil added to reduce sticking. Make sure water is in a rolling boil before adding Pierogi's and cook only 12 to 18 per pot. Stir very gently using wooden spoon. Boil for 10 to 12 minutes after they rise to top of pan, stir occasionally. Drain carefully and rinse.

Chop 1 large onion and saute in 1 to 2 sticks of butter. Pour over top of hot Pierogi's. Serve as is, or using small amounts of onion and butter mixture to fry Pierogi's, cook until golden brown. Pierogi's freeze well if placed in single layers and coated with onion and butter mixture to prevent sticking. Fry only after thoroughly thawed. Makes 50 large or 80 small Pierogi's.