Claiborne & Churchill's Spicy Pumpkin Cream Soup

2 tablespoons butter
1 medium onion, chopped
1 can pure pumpkin (solid-pack) or 3 cups fresh-cooked pumpkin puree
3 cups chicken broth
Spices: a dash each of cinnamon, ground cloves and nutmeg
2 tablespoons finely diced fresh ginger
Half-pint heavy cream
Salt and pepper

Sautée the onion in butter in a heavy saucepan until soft. Add pumpkin, chicken broth, and spices and simmer gently for 20 minutes. Allow to cool a little and purée in a blender or food processor, or put through a strainer, then return to the pan. Stir in the heavy cream and heat thoroughly (do not boil). Season with salt and pepper.