Preheat oven to 375°. Spray a 1½-quart baking dish with cooking spray.
On a large rimmed baking sheet, combine squash, carrots, onion, garlic, ginger, oil, 1 teaspoon salt, and pepper, tossing to coat well.
Bake until vegetables are tender and browned, about 50 minutes. Let cool enough to handle. Discard ginger.
In the work bowl of a food processor, add roasted vegetable mixture; process until smooth. With processor running, add cream and melted butter. Add thyme, rosemary, and remaining 1½ teaspoons salt; process until just combined. Pour squash mixture into prepared baking dish.
Bake until mixture is bubbly and browned around edges, 30 to 32 minutes. Garnish with thyme and rosemary, if desired. Serve warm.
Recipe by Southern Lady Magazine at https://southernladymagazine.com/winter-squash-and-carrot-puree-recipe/