Source: The New Basics Cookbook
Preheat oven to 350F. Cut squash in half lengthwise. Scoop out seeds. Place squash halves in roasting pan. Place 1 tablespoon of butter and 1 teaspoon of brown sugar in cavity of each squash half. Arrange carrots and onion slices around the squash. Pour 2 cups of the stock in the pan, cover tightly with aluminum foil and bake for 2 hours.Remove pan from oven and allow vegetables to cool slightly. Scoop squash pulp out of skins and place in a soup pot. Add carrots onions and cooking liquid. Add remaining 8 cups chicken stock and mace, ginger, cayenne, and salt. Bring to a boil. Reduce heat and simmer uncovered for 10 minutes. Puree the soup in batches in blender or food processor until smooth. Return it to the pot, adjust the seasonings, and heat through. Serve each portion garnished with a dollop of creme fraiche (below) and sprinkling of chives.