Serves 18
Preheat oven to 350°F (175°C).
Cut the spaghetti squash in half and place it face-down in a 9×13-inch (23×33-cm) pan. Bake uncovered for 40 minutes. Set aside.
In a large pot, sauté the onion in oil until golden. Add the vegetables to the pot with water to cover. Bring the soup to a boil and add seasonings. Lower heat and simmer for 1 hour, or until the vegetables are cooked through.
Blend with an immersion blender until mostly pureed, adding more liquid if necessary to achieve desired consistency.
Scrape the strands of the spaghetti squash into a bowl. Gently separate the strands with two forks. Add it to the soup and stir well.
Note: Instead of chicken soup mix, you can substitute chicken soup for half the water for additional flavor.