1. Preheat the oven to 400°. Slice the squash in half lengthwise, scoop out the seeds and fibrous pulp and separate the seeds from the stringy pulp. Reserve the seeds. Use a sharp knife to score the neck portion of the squash several times, then rub the flesh with olive oil and season with salt. Roast the squash cut side down on a baking sheet until tender and lightly caramelized, about 1 hour.
2. In a colander, rinse the reserved seeds and dry with paper towels. Place on a sheet pan and toast in the oven for 5 minutes, until golden and fragrant. In a small bowl, whisk together the melted butter, cayenne pepper, cinnamon and a large pinch of salt. Toss the seeds in the mixture and set aside.
3. In a medium stockpot set over medium heat, heat about a tablespoon of vegetable oil. Add the onions, carrots, celery and jalapeño, if using, and cook, stirring often, until tender, about 10 minutes. Add the maple syrup and cook, stirring frequently, until the syrup is reduced by two-thirds, about 5 minutes. Remove the stockpot from the heat and set aside.
4. When the squash is done, remove it from the oven and allow it to cool briefly. Remove the squash flesh from the skin and mix it into stockpot with the onion and carrot mixture. Return the stockpot to the stove. Turn the heat to medium, add the chicken stock and cream, bring to a simmer and cook for 10 minutes. Carefully transfer the soup to a blender and blend until smooth OR Use a immersible blender which is much easier in the cooker, without the chance of spilling. Season with the cider vinegar and salt. Serve soup hot with apple, cilantro and toasted seeds.