Heat the oil over low heat in a 4 1/2 quart Dutch oven. Peel and finely mince the onion, and add it to the pot. Cook, stirring often, until the onion begins to soften, about 2 minutes.
Add the chicken broth, pumpkin, orange juice concentrate, ginger, cayenne pepper and salt. Stir to mix well. Raise the heat to high, and bring the soup just to a boil.
Reduce the heat to low and add the cream. Simmer, stirring frequently, until ready to serve, up to 30 minutes. The soup can also be made 2 days ahead, refrigerated in an airtight container and reheated.
Serves 8. 102 calories, 7 g fat, 2 g protein, 10 g carb.