Filling: Cook onion in butter. Mix with potatoes, and add cheese while the mixture is still hot. You may substitute Cheez Whiz for the cheddar. Let filling cool before using (place in fridge.) If you are using the alternate filling, simply mix those ingredients together.

Making Varenykys: Set a large pot of water to boil. Form walnut-sized balls of the filling. Roll out dough on floured surface fairly thinly (3 millimeters, or 0.125 inch). You will probably need to add flour as you roll. Cut out circles approximately 7 1/2 centimeters (3 inches) in diameter (a wider-mouthed glass should do fine.) Press scraps into a ball. Place filling ball in center of dough circle. If the dough has a less-floury side, keep that side up. Fold dough over ball, and pinch edges to form a half circle. To prevent perogies with"horns", I pinch at the top ("90 degree mark") of the perogy first, then pinch at the 180 and degree edges, working up to the 90 degree mark. You can cheat pinching the perogies by smearing water on the filling side of the dough at the edges, and keep your fingers floured when you pinch (on the non-filling side.) In order to prevent perogies from drying out, keep finished perogies on a floured surface, and cover with a floured clean dishcloth.

Cooking: Place several perogies in boiling water. Stir once, gently with a slotted spoon. Perogies are done when they float for a minute (this will take 2-3 minutes). Fry about 1/2 cup of butter and 1 diced onion until onion are slgihtly bronw. Take out and drain the perogies with the slotted spoon. Place in a bowl and drizzle with melted butter and gently shake to distribute the butter to keep perogies from stikcing together. Cook, drain, and drizzle the other perogies in the same manner. Serve with sauteed butter and onion sauce or with a dab of sour cream.