Preheat the oven to 425°F. Place the cubed butternut squash on a baking sheet lined with foil and drizzle with 2 tablespoons canola oil. Season with ½ teaspoon kosher salt and freshly ground pepper and toss well to coat. Roast the squash for 15 minutes or until caramelized but not browned. Set aside.
In a dutch oven or heavy bottom pot, melt the butter with 1 tablespoon canola oil over medium. Add the onion, carrot, and garlic and cook until the onion is softened, about 5 minutes, stirring often so the vegetables don't burn.
Add the roasted butternut squash to the pot, along with the chicken broth and herb bouquet garni. Bring to a boil then reduce to a bubbling simmer and cook for 15 minutes or until the carrots are softened and the broth has reduced by ⅓. Stir in the honey. Remove the herbs and transfer the vegetables and broth to a blender (do so in batches if needed). Top the blender with the lid minus the center plug so that the hot liquid breathes (otherwise the heat will cause the mixture to explode when blending). Cover the lid with a dishtowel and blend the mixture until smooth. Add back to the pot and stir in the cream or milk. Taste for seasoning and add more salt and pepper if needed, then cook over medium for another 5 minutes or until warmed through.
To serve, thin the sour cream with 1-2 teaspoons of water or milk and drizzle over the soup. Garnish with herbs or toasted pumpkin seeds.