Preheat your oven to 400°F (200°C). Spread the cubed butternut squash and sliced carrots evenly on a baking sheet. Drizzle with olive oil and toss to coat. Roast for about 25-30 minutes, until the edges are caramelized and veggies are tender.
While the vegetables roast, heat a splash of olive oil in a large pot over medium heat. Add the chopped onion and cook for about 5 minutes, stirring occasionally, until translucent and fragrant.
Add the minced garlic to the pot and cook for another minute until it becomes fragrant. Be careful not to let it brown.
Once the roasted vegetables are done, add them directly to the pot with sautéed onion and garlic. Pour in the vegetable broth and bring the mixture to a gentle simmer. Let it cook for about 10 minutes to meld the flavors.
Remove the soup from heat and use an immersion blender to blend until smooth and creamy. Alternatively, carefully transfer the soup to a blender in batches and purée until silky.
Return the blended soup to low heat, season with salt and pepper to taste, and stir well. Warm through for a few minutes, adjusting seasoning as needed.
Serve the soup hot, garnished with a swirl of olive oil or fresh herbs if desired. Enjoy the creamy, earthy flavors of this comforting dish.
