1. Peel, seed and dice the squash.
2. Put it in a pot with the vegetable broth, water, cinnamon stick, and salt, and simmer until tender, about 40 minutes.
3. Discard the cinnamon stick. Melt the butter and gently cook the onions in it, stirring occasionally until it begins to caramelize.
4. Peel, core and thinly slice the pears and add them to the onions. Continue cooking for about 5 minutes, stirring often.
5. Add the wine, cover, and simmer for 10 minutes.
6. Add the pear mixture to the soup and purée everything in a blender in batches.
7. Add some yogurt cheese if desired to make it creamier.
8. Heat the soup again just to a simmer, but do not boil.
9. Serve plain or garnished with chopped chives or sprigs of cilantro.