Combine mushrooms,onion and chicken stock in soup pot and simmer for 20 minutes.
In another saucepan, melt four tablespoons butter over medium heat gradually stirring in the flour until smooth. Remove from heat and gradually stir in the milk and cream. Return to medium heat and cook stirring constantly, until thickened. Season with salt and pepper. Stir mushroom-chicken stock into sauce.
In a small frypan heat the remaining two tablespoons butter and add escargot, garlic, parsley and green onion, sauté for 2 minutes. Add to soup along with wine.