Marinate the mushrooms. Pour water into a saucepan and put the champignons in it. Sprinkle with salt, sugar and spices. Bring to a boil over medium heat and add vinegar and garlic. Cook the champignons for 15 minutes.
Prepare the dish. Heat the vegetable oil in a frying pan, pour in the onion. Fry until transparent. While the onion is frying, cut the mushrooms into slices. Next, fry the marinated mushrooms in a frying pan with the onion for 6 minutes. Add the potatoes, mix thoroughly. Cook for 20 minutes, stirring occasionally.