Peel the onion and chop finely. Sort the mushrooms, peel and wash.
Pour oil into a heated frying pan and add boletus mushrooms. Fry the mushrooms over medium heat until all the liquid has evaporated and a golden crust appears. Then add the onion and cook, stirring, until it becomes soft. Don't forget to add salt.
Pour sour cream into the fried onions and mushrooms, add spices to taste. Simmer the dish over very low heat, covered, stirring occasionally to prevent it from sticking to the bottom of the pan, until it reaches a uniform thick consistency.
Serve the dish hot with bread and herbs.