Preheat the oven to 350°F (176°C). Cut the peeled squash into pieces and place them on a baking sheet. Roast in the oven until golden and tender.

Heat a pot over medium heat and add the olive oil. Sauté the onion and garlic together until softened.
Transfer the sautéed onion and garlic to a blender along with the roasted squash pieces, broth or water, nutmeg, salt, and pepper. Blend until smooth. Repeat as needed until all ingredients are blended. Return the pumpkin soup to the pot and heat through.
Serve topped with roasted squash pieces or sprinkle with toasted pumpkin seeds.