For the pirogi dough, sift the flour onto your countertop and make a mould in the middle. Add an egg and some water and work both into the flour until you have a smooth mixture. Knead for another 3 minutes and then let it rest, covered, in the fridge for 30 minutes.
Bring a pot of salted water to boil and cook the potatoes with their skins on. Peel the onion and garlic and chop both. Wash the chives and cut into fine rings.
Drain the cooked potatoes and when they have cooled a little, peel them with a small knife and press them through a potato ricer into a bowl.
Put a frying pan on the stove and add the butter cubes. Add the Mildessa Sauerkraut and sauté over medium heat. Then add the diced onions and garlic and continue to sauté until the onions turn translucent. Season the sauerkraut with salt, pepper and chives. Then season the potatoes with nutmeg and add the mixture to the sauerkraut. Mix everything together well and leave to cool.
Tip: If you cook the potatoes with their skins on, they won't water down. The potatoes retain their flavour and all the important ingredients. In addition, the skin is very easy to remove - so less potato ends up in the waste.
Heat a pot of salted water to boiling.
Roll out the dough and cut out circles (approx. 10 cm in diameter) with a glass. Put a tablespoon of the potato-sauerkraut filling on each of the dough circles. Now separate an egg and brush the edge of the dough circles with a little egg yolk (this helps the pierogi edges to stick together) and then fold them into half-moons. Drop the finished pierogi into the bubbling water and simmer for about 3 minutes. Remove them with a skimmer.
Tip: You can use the leftover egg white to make a homemade quiche dough the next day, for example.
Serve the hot pierogi with fresh sour cream. If you have any filling left over, you can serve it as a garnish. Sprinkle with chives and freshly ground black pepper.