Cut the leek into thin rings, place it in a deep saucepan with thick walls, and start simmering in olive oil. Then add a little salt so the leek releases its juice.

Cut the potatoes into thin slices (it’s easiest to do this with a potato peeler) and add them to the saucepan with the leek. Add salt, mix well, add a little water, and simmer over low heat until cooked.

Finely chop the parsley and add it to the saucepan. Add sour cream and mix well, then simmer for another 5 minutes. Add black pepper.

The result should be a creamy, soft, almost-puree with plenty of thick sauce.

It can be eaten separately or as a side dish.