To make the filling, peel the potatoes and chop into quarters. Bring a pan of salted water to the boil, add the potatoes and simmer for 20 mins until soft. Drain and leave to cool. Meanwhile, fry the onions gently in the butter for 8 mins until soft and translucent. Set a couple of tablespoons aside to serve with the dumplings, if you like. Add the onions to the potatoes, season with salt and pepper, then mix and mash everything thoroughly.

Mix the flour with 450 ml tempid water, 10 g salt and the oil, then knead thoroughly to make a smooth dough.

Leave to rest for 15 mins.

Spilt the dough into two and roll the first half thinly to 1-2 mm on a lightly floured surface.

Cut out the circles with a rim of a glass or an 8 cm pastry cutter, then fill each one with 1 heaped tbsp of stuffing. Pinch the edges of the pierogi together with a little water, making sure they are firmly sealed.

Any leftover stuffing can be frozen to make more pierogi.