Over medium heat saute onion and olive oil until onion is clear. Add garlic and ginger. Saute about 5 minutes. Add sage, cloves, cinnamon. Add broth and cubed squash. Raise heat and bring to a boil. Reduce heat, cover and simmer for approx. 30 minutes or until the squash crushes easily against the side of the pan with the spoon. Transfer the soup to a blender and puree. Transfer back to pot and heat thoroughly. Season with salt and pepper to taste. Garnish with chopped chives.