Heat olive oil in a large dutch oven over medium-high heat and add onions, one tsp salt, and pepper. Cook until soft, about five minutes.
Add garlic, sage, and ginger and cook for another three minutes.
Add stock, coconut milk, squash, cinnamon, nutmeg, and the rest of the salt and stir. Bring to a boil then lower heat to medium, cover, and cook for thirty minutes, or until squash is fork-tender.
Either use a hand blender or pour soup into a blender and blend until smooth. Blend in half and half and serve.