Dough:

Combine water, egg, oil and blend well. Add flour and 1 tsp of the
salt. Knead until smooth and soft (8 minutes approx). Put dough into
a lightly oiled bowl, cover and rest for 20 minutes.

Potato Filling:

Combine (slightly cooled) mashed potatoes and grated cheddar in a
bowl. Saute onions in butter and add to mashed potatoes. Add in the
remaining salt (1/2 tsp) and pepper to taste.

Take small pieces of the dough and roll it out until it is very thin
(1/8" or so). Take a coffee mug (or round container of your choice)
and cut our a circular shape.

Into the middle of the circle, drop 1/2 to 1 tsp of the potato
mixture . Fold the circle in half and seal edges by pinching them
together. This should leave you with a half moon shape.

When you have completed sealing the pyrohy, it should be laid between
two clean towels (this prevents it from drying out). Once you have
made all of the pyrohy possible (when either your dough or potato
runs out), set a pot of water to boil.

In batches of 6-8 (depending upon how much your pot can hold), cook
the pyrohy until they are floating. Remove from water, place in a
casserole dish and melt some butter or margerine on the batch of
pyrohy to keep them separated nicely. Continue this until they are
complete.

Now they're ready to eat. Also at this time you can freeze them in
batches (I find that batches of a dozen work well). I love pyrohy
with sour cream, chives or fried onions and little pieces of bacon
(shkvarky--optional).

The next day, you may find that frying the pyrohy give you an even
more pleasant taste!