In a large soup pot, heat the olive oil over medium heat. Add turmeric, cumin, ginger, onion, and a pinch of salt. Sauté for 3 minutes. Add squash and another pinch of salt, then sauté for 1 minute more.
Add 1 cup broth and deglaze the pot. Cook until it reduces to ½ cup.
Add remaining broth, water, and cinnamon stick. Bring to a boil, then reduce heat to a simmer and add coconut milk. Simmer gently for 15 minutes, or until squash is tender. Remove the cinnamon stick and then purée with a handheld immersion blender or standard blender. You will need to do this in batches if using a standard blender. Fill the blender halfway each time and remove the central part of the blender lid, or vent the lid slightly before blending. This allows steam to escape and prevents the lid from popping off. Cover the lid with a dish towel to prevent splashing. Repeat in batches until all the soup has been blended.
Season with lime juice, maple syrup, and another pinch of salt before serving.