Heat butter and fry the onions and garlic till soft.
Chop half of the mushrooms coarsely and add to it. Fry for about 5 minutes.
Add the flour while stirring well. Cook for another 5 minutes.
Gradually add the stock and bring to a boil.
Add salt, bay leaves, black pepper powder and simmer for 20-25 minutes.
For a clear soup, sieve it. Otherwise liquidize in a blender and strain.
Finely chop the remaining mushrooms and add along with the milk. Bring to a boil and simmer for 15 minutes.
Add the lemon juice and cream and reheat (do not boil).
Garnish with the fried onion rings and chopped parsley.