During this time, chop the parsley and remove the thyme leaves from the stems. When the mushrooms are tender, add the herbs and tomato paste. Simmer about 1 minute. Add the white wine, broth, parmesan cheese, salt and pepper. Bring to a boil, then reduce to a simmer. Simmer 1 hour, then serve with more parmesan as garnish, plus croutons if you like.