Melt butter in a heavy pot over low heat. Add the carrot, celery, onion and generous pinch of salt. Cook, stirring often to avoid any colour, until very sweet and tender, about 15 minutes.
Increase heat to high, add the wine and cook until almost entirely evaporated. Make a bouquet garni: combine the parsley, thyme, cloves, star anise, bay leaf and peppercorns and wrap tightly in cheesecloth, or the outer layer of a leek, then tie with kitchen twine. Add the bouquet garni to the pot along with the chestnuts and stock. Bring to a boil, then reduce the heat to low and simmer, covered, for 20 minutes.
Remove the bouquet garni from the pot. Use your hands (or tongs, if too hot) to squeeze all the liquid from the bouquet garni back into the pot. Really wring it out with some force; those herbs have so much flavour to give! Blend the soup until completely smooth, then taste and add salt if needed.
Ladle the soup into warm bowls. Finish with black pepper and lots of Flamingo Estate White Truffle Olive Oil.