Melt butter in a large saucepan over medium heat. Add onion and cloves, and sauté for 4-5 minutes, until onions are translucent. Add chestnuts and broth and bring to a boil. Lower heat and simmer 20 minutes.
Blend in batches until smooth. Return to saucepan to rewarm.
Sat and pepper to taste.
Garnish with 1 tablespoon of crème fraiche or sour cream and a sprinkle of parsley.
Serves 6.