Roast the Vegetables: Preheat oven to 400°F (200°C). Toss butternut squash and carrots with olive oil, salt, and pepper. Spread on a baking sheet and roast for 25-30 minutes, or until tender and slightly browned.
Sauté the Aromatics: While the vegetables are roasting, heat a tablespoon of olive oil in a large pot or Dutch oven over medium heat. Add the chopped onion and cook until softened, about 5 minutes. Add the minced garlic and cook for another minute until fragrant.
Combine and Simmer: Add the roasted butternut squash and carrots to the pot. Pour in the vegetable broth, ground ginger, and ground nutmeg. Bring to a boil, then reduce heat and simmer for 15-20 minutes to allow the flavors to meld.
Blend Until Smooth: Use an immersion blender to blend the soup until smooth and creamy. Alternatively, carefully transfer the soup to a regular blender (in batches, if necessary) and blend until smooth.
Season and Serve: Season the soup with salt and pepper to taste. Serve hot, garnished with your favorite toppings.
