Clean, wash and dry mushrooms. Peel and chop onion and garlic. Heat the oil in a large pan. Fry the mushrooms in it, possibly in portions until golden brown. Fry the onion and garlic briefly, season to taste
Dust the mushrooms with flour and sweat them. Deglaze with tomatoes and stock. Bring to the boil and simmer while stirring for about 15 minutes. Stir in cream, heat up. Season to taste with salt, pepper and sugar. Wash the basil, cut into strips, sprinkle over it