Peel potatoes and onions and chop them. Slice mushrooms and chop parsley. Heat oil in a saucepan and sauté onion and mushrooms. Pour in soup, add herbs and bring to the boil. Add the potatoes, cover and boil 30 minutes until tender. Remove bay leaf and puree the soup for 30 seconds. Stir in cream and season to taste. No more boil.