Soak the mushrooms for 30 minutes in cool, salted water, then peel them and rinse again under running water. Cut the boletus legs into pieces and the caps into halves. Peel the onion and cut into rings. Also wash and peel the potatoes, cut into strips.
Heat the oil in a frying pan and add the boletus. Add salt and pepper to taste, cover with a lid and fry the mushrooms over low heat until the juice has completely evaporated, 30-35 minutes. After cooking, remove the mushrooms from the pan for a while.
Fry the potatoes cut into strips over medium heat for about 10-15 minutes, then add the onion and fry until the potatoes appear crusty. At the end of frying, add the prepared mushrooms and mix well.
Serve the fried potatoes with boletus, sprinkling some herbs on top if desired.