In a soup pot or Dutch oven, heat 2 tablespoons olive oil over medium heat. Add 1 cup diced onion and ½ cup peeled & chopped carrot; season with ¾ teaspoon sea salt. Cook until softened, about 5 minutes.
Stir in 2 garlic cloves, 1 teaspoon fresh thyme leaves, ¼ teaspoon ground cinnamon, and ⅛ teaspoon ground nutmeg. Cook for another 1 minute until fragrant.
Add the cubed 6 cups butternut squash and broth. Bring to a boil, then reduce heat, cover, and simmer until squash is fork-tender, about 20–25 minutes.
Use an immersion blender to puree the soup right in the pot, or carefully transfer in batches to a blender. Blend until velvety smooth.
Stir in heavy cream or coconut milk, if using. Taste and season with salt and pepper as needed.
Ladle into bowls and garnish with your favorite toppings.