Preheat the oven to 400°F. On a rimmed baking sheet lined with parchment or aluminum foil and sprayed with nonstick spray, toss the butternut squash, carrots, and rutabaga with the 2 tablespoons olive oil and salt and pepper.
Roast the vegetables in the oven for 20 minutes. While the vegetables begin roasting, make the glaze.
In a food processor or blender, combine the scallions, pureed chipotles in adobo, honey and 2 tablespoons olive oil. After the vegetables have been in the oven for 30 minutes, remove them from the oven, and reduce the oven temperature to 350°F. Spoon the glaze mixture over the vegetables, toss to combine well, and return the baking sheet to the oven. Roast for another 20 to 30 minutes, until the vegetables are very tender and nicely caramelized.
You can either transfer the vegetables to a food processor or a blender with 1 cup of the broth and puree, then transfer to a pot; or, use an immersion blender and puree the vegetables with 1 cup of the broth right in a pot. Either way, combine the pureed vegetables with the remaining 2 cups broth in the pot, and heat until everything is hot and smooth. Stir in the cream if using.