Preheat oven to 425 degrees F and line a baking sheet with parchment paper or foil for easy cleanup. Carefully cut the pumpkin into 4 equal pieces and scoop out the seeds. You won't need the seeds for this recipe.
Brush 1 tablespoon olive oil over pumpkin flesh and place the quarters, cut sides down, onto baking sheet. Roast for 35 to 45 minutes, until the orange flesh is easily pierced with a fork. Set aside to cool for a few minutes.
Meanwhile, heat the remaining 2 tablespoons olive oil in a large pot over medium heat. Add onion and garlic to the pot. Cook, stirring occasionally, until onion is translucent, about 8 to 10 minutes.
Peel skin off of the cooled pumpkin quarters and discard the skin. Roughly mash the pumpkin flesh with a potato masher.
Add the pumpkin flesh and vegetable broth to the pot. Stir in the salt, cinnamon, nutmeg, cloves, cayenne pepper (if using) and black pepper. Bring the mixture to a boil, then reduce heat and simmer for about 10 to 15 minutes, to give the flavors time to meld.
Once the pumpkin mixture is done cooking, stir in the coconut milk and maple syrup. Remove the soup from heat and let it cool slightly. Use an immersion blender, potato masher or regular blender (see note below) to blend the soup until smooth. Taste and adjust as necessary.
Ladle the soup into bowls. Sprinkle pepitas (optional) or a dusting of cinnamon on top and enjoy!