Preheat oven to 400F/200C. Place the sweet potatoes cut side down on a parchment line baking sheet and roast until tender, about 25 – 30 minutes. Clean out and discard the squash or pumpkin seeds. Brush the flesh with a little olive oil and season with salt and pepper. Roast on a separate lined sheet pan until tender, about 45 minutes.
While the sweet potatoes and squash/pumpkin are roasting, heat the olive oil in a large soup pot over medium flame and sauté the carrots, onions, leeks, and fennel until soft, about 15 minutes. Add the garlic and stir for a minute or so. Stir in the spices and cook together with the onion mixture for 2 – 3 minutes. Turn off the heat.
Remove the sweet potatoes and let them cool slightly. When the squash is tender, remove that too. Using a tablespoon remove the soft flesh from both.
Turn the heat back on the onion – spice mixture and add the sweet potato / squash pulp. Stir to combine. Add 8 cups water or stock. Season with salt and pepper. Bring to a boil then reduce heat and simmer the soup until the carrots and vegetables are very tender.
Using an immersion blender or food processor, puree the soup until very smooth. Place back in the pot. Dilute as necessary to achieve a velvety rich-bodied consistency. Add the balsamic and honey and warm through. Adjust seasoning with additional salt, pepper, or spices.
Remove and serve, garnished with a little balsamic, Greek yogurt and/or heavy cream.