With a sharp chef's knife, split the squash in half lengthwise and scrape out the seeds with a spoon. Score the insides of each half several times with a knife.
Place each half in a large baking pan, cut side up. Add about 1/4 inch of water to the bottom of the pan. Coat the inside of each squash half with 1/2 tablespoon olive oil. Add a dash of salt and drizzle a teaspoon of maple syrup to each half. Place in oven and bake for about 1 hour or until squash is very soft and tops are golden brown. Set aside and allow to cool.
Scrape out flesh from squash halves with a spoon and transfer to a food processor (discard skin). Process until smooth. Set aside.
In a large soup pot, heat 2 tablespoons olive oil over medium heat. Add onion and saute for 5 minutes, until soft and translucent. Stir in kale and cook for 1 minute.
Add squash puree and 3 cups of water (or more to reach desired consistency). Bring just to a boil. Season generously with salt and pepper. Serve and garnish with reserved bacon if desired.