Preheat your oven to 425°F. Line two baking sheets with parchment paper.

Toss the butternut squash, sweet potato, and carrots with olive oil, salt, and pepper. Spread them out on the prepared baking sheets. Roast for 35-40 minutes, or until a fork easily pierces the vegetables.

While the vegetables roast, heat olive oil in a large stockpot over medium heat. Sauté the diced onions until they become translucent and soft, seasoning with a pinch of salt. Add the minced garlic and cook for another minute until fragrant.

Add the roasted vegetables to the pot along with the vegetable broth, chicken broth, cinnamon, and nutmeg. If using unsalted broth, you may need to add salt to taste.

Use an immersion blender to puree the soup until smooth. If you don’t have an immersion blender, carefully transfer the soup in batches to a regular blender.

Remove the pot from heat. Stir in the milk and heavy cream, adjusting the consistency with more broth or cream if needed. Taste and adjust seasoning as necessary.

Ladle the soup into bowls and serve with croutons or crusty bread.