Wash vegetables, peel, dry. Onion cut into half rings. Grate the carrots. Cut the champignons into slices. Chop cabbage. In heated sunflower oil, fry the onions until transparent. Add carrots to the onion and fry too. Add mushrooms, fry over high heat, stirring constantly, until the liquid evaporates. Add cabbage, fry often stirring. In a fried cabbage add tomato paste, salt, sugar, ground pepper, vinegar if desired. Stir well, cover and simmer for 2 minutes.