This soup is perfect in winter-time. The root vegetables are comforting and the ginger is warming. Increase or decrease the amount of ginger to suit your taste. Chicken or vegetable stock may be substituted for the water. Either a blender or food processor can be used to puree the soup. If desired, add cream instead of yogurt to enrich the taste.
Place the squash, sweet potatoes, onion, ginger, and garlic in a large pot. Pour in enough water to cover the vegetables. Bring to simmer over medium heat, and cook until vegetables are tender and can be easily pierced with a fork, 30 to 45 minutes.
Remove pot from heat. Place soup in batches into a blender or the bowl of a food process. Pulse until smooth. Return soup to pot, and whisk in yogurt. Season with salt and pepper to taste. If necessary, reheat soup over low heat, but do not allow to boil.
Per Serving: 207 calories; protein 5.4g; carbohydrates 47.3g; fat 0.7g; cholesterol 1.8mg; sodium 110.9mg.