To make the dough, stir together the flour and salt. Add the eggs and sour cream and use two butter knives to cut them into the dough. Gradually add the water, cutting with the knives until all of the flour is incorporated. Form the dough into a loose ball (it will be sticky) and cover the bowl with plastic wrap. Let sit for 30 minutes.
When ready to make the pierogies, bring a large pot of water to a slow boil. Take a piece of dough and roll it out to about 1/16" thick. Place a heaping tablespoon of dough on the lower third and stretch the dough over it. Use a wineglass or round cutter to make a half moon. Pierce the edges with a fork to seal. Continue working until you have 6-12 pierogies made. I boiled 6 at a time but you can do up to a dozen. When you have some ready, drop them in the boiling water and cook until they float for 1 minute. Remove with a slotted spoon and drizzle with a little melted butter to prevent sticking.
Repeat until all filling is used. Once boiled, you can serve the pierogies immediately or you can fry them.
If you want to fry them, saute a little onion in a pan then add the pierogies and cook until golden. They are also delicious with some bacon or served with sour cream.
Recipe by white plate blank slate at https://whiteplateblankslate.com/potato-cheese-pierogies/