Pierogi with potatoes and quark

Method
Prep:1hr  ›  Cook:10min  ›  Extra time:40min  ›  Ready in:1hr50min 

1. To prepare the filling: Boil the peeled potatoes in salted water; drain and mash well. Allow to cool completely.
2. Melt butter in a pan over medium heat; add onions and fry until softened and golden brown in colour.
3. Mash the quark well in a large bowl. Add cooled potatoes and onions (together with the fat from the pan). Season to taste with salt and plenty of pepper.
4. To prepare the dough: Place flour in a large bowl and make a well in the centre. Crack the egg into the well. Start adding the water in a steady stream, mixing the flour and egg with your hand. The dough shouldn't be too sticky, so stop adding water when you feel there's too much.
5. When the dough comes together, transfer it onto a lightly floured surface and knead until soft and smooth.
6. Divide into smaller portions, take one and cover the rest with a clean drying cloth. Roll out the 1st piece until very thin (2mm or less). Use a drinking glass or a round cutter to stamp out rounds. Place the rounds on a lightly floured surface and cover with a clean cloth. Gather up the remaining dough and knead it again with the next portion of dough you use. Repeat the rolling out and cutting procedure with the remaining dough.
7. Take a teaspoon of the filling and place in the centre of a round. Fold the round and seal the edges pinching well. Set aside on a floured surface. Cover with a clean cloth.
8. To cook the pierogis: Bring a large pot of salted water to a gentle boil. Add pierogis in batches into the gently boiling water, stirring to prevent them from sticking to the bottom of the pot. Cook for about 7 minutes from the moment they float on the surface. Take out with a slotted spoon and pour over melted butter so they don't stick.

To freeze:

If you made too many pierogis to eat in one day, you can simply freeze them. Place stuffed, uncooked pierogis on a generously floured cutting board, one by one (but not touching each other) and place in a freezer. After approximately one hour, when they are frozen, transfer pierogis into a freezer bag. To serve, drop frozen pierogis into a large pot of salted, gently boiling water and proceed with the last step of this recipe.