I used the NYT recipe by Bar Prasowy. Found here:
https://cooking.nytimes.com/recipes/1020983-pierogi-ruskie-potato-and-cheese-pierogi
I recommend adding cheddar cheese into the filling and making a double batch of dough, otherwise, you will have a lot of filling leftover.
Pierogi are also easy to freeze. Once boiled, set out to dry and then put in a freezer-safe bag and freeze!