- STEP 1
In a large bowl, stir together the flour and salt. In a separate bowl, whisk together the butter, sour cream, eggs, egg yolk and oil. Stir the wet ingredients into the flour until well blended. Might seem like there is too much flour but make the effort to lightly knead dough with hands to combine. Cover the bowl with a towel, and let stand 30 minutes.
- STEP 2
Place potatoes into a pot, and fill with enough water to cover. Bring to a boil, and cook until tender, about 15 minutes. Drain, and mash, then add shredded cheese while still hot. Season with onion salt, salt and pepper. Set aside to cool.
- STEP 3
Separate the pierogi dough into two balls. Roll out one piece at a time on a lightly floured surface until about 1cm thick, but not too thin so that it tears. Cut into circles using a cookie cutter, pierogi cutter, or a glass 4-5cm in diameter. Brush a little water around the edges of the circles, and spoon some filling into the centre. Fold the circles over into half-circles, and press to seal the edges to create half moon shape. press edges with fork. Place pierogi on a cookie sheet, and freeze. Once frozen, transfer to freezer storage bags or containers.
- STEP 4
To cook pierogi: Bring a large pot of lightly salted water to a boil. Drop pierogi in one at a time. They are done when they float to the top. Do not boil too long, or they will be soggy! Remove with a slotted spoon. the dough is meant to have a doughy texture.
- STEP 5
After boiling you can fry pierogi for extra crisp, I like to do this in the pan used to make caremalised onions. put pan on medium to high heat, add 2 tbsp of vegetable oil and fry pierogi until a little golden on either side.
- STEP 6
Caremalised onions: roughly dice onions then place on pan on low heat. Wait until onions have become translucent and a slightly golden. Add sugar and wine/balsamic vinegar and continue to cook on medium heat untill onions are dark golden brown/