Pierogi ruskie (raviolis polonais aux pommes de terre et au fromage)

Instructions

1. Mix the flour, salt, oil and lukewarm water to get a soft dough, then knead for 8 minutes until smooth.
2. Cover the dough and let it rest for 30 minutes at room temperature.
3. Cook the peeled potatoes in boiling salted water for 20 minutes, then mash them.
4. Thinly slice the onions and cook them gently in the oil for 10 minutes until golden, then mix half of them with the mash and the fresh cheese.
5. Season the filling with salt and pepper, then let it cool.
6. Roll the dough out thinly, cut 8 cm rounds and put a spoonful of filling in the centre of each.
7. Fold into half-moons, pinching the edges well, then place the pierogi on a floured surface.
8. Cook them in boiling salted water for 3 to 4 minutes after they rise to the surface, drain and brown them in butter with the remaining onions.