Heat the butter in a medium saucepan, add the onion and cook for 2 - 3 minutes. Stir in the mushrooms and cook a further 2 minutes. Combine the soup mix, water and wine. Stir into the onion mixture. Bring to the boil, stirring constantly. Add the chicken and cream and simmer for a further 10 minutes, stirring frequently. Garnish with parsley.