Preheat your oven to 400°F (200°C). Spread the cubed pumpkin evenly on a baking sheet, drizzle with olive oil, and toss to coat. Roast in the oven until tender and slightly caramelized, about 25-30 minutes.
While the pumpkin roasts, heat a large pot over medium heat. Add chopped onion and cook, stirring occasionally, until translucent and fragrant, about 5 minutes. Add minced garlic and cook for another minute until fragrant.
Once the pumpkin is roasted and cool enough to handle, transfer it to the pot with the sautéed onions and garlic. Stir to combine and let the flavors meld for a couple of minutes.
Pour in the vegetable broth and coconut milk, stirring well. Bring the mixture to a gentle simmer and cook for 10 minutes, allowing the flavors to deepen and the soup to develop a rich aroma.
Use an immersion blender or transfer the soup in batches to a blender, then blend until smooth and velvety. Be cautious of hot splashes during blending.
Return the pureed soup to the pot if using a blender, and gently reheat over low heat. Season with salt, pepper, and a dash of cinnamon to taste, stirring to combine.
Once heated through and seasoned to your liking, ladle the soup into bowls. You can garnish with a sprinkle of cinnamon or a drizzle of coconut milk for presentation.
