Lightly coat a large, nonstick pot with cooking spray. Add the oil and set over medium heat. Sauté the onion, garlic and ginger for 5 minutes or until the onions are just softened.
Add the squash, stock, chili sauce, fish sauce and salt. Bring to a boil, then reduce the heat to low. Cover and simmer for about 20 minutes or until the squash is tender.
Purée the soup in a blender or food processor in batches. Return the soup to the saucepan and add the coconut milk and honey. Heat through.
Serve the soup in bowls, and garnish with cilantro or basil.