Preheat oven to 375° F. Slice the squash into large slices (see photo in post) and place on baking sheet lined with parchment paper. Roast for 1 to 1 1/2 hours or until flesh is easily pierced with knife, all the way down to the rind.
In a dutch oven or large stockpot, heat oil over medium high heat. Add chopped onion and saute until caramelized (about 5-10 minutes). Add the mint, ancho powder, cinnamon, sticks, and coriander and saute with onion a couple of minutes.
Add the broth to the pot. Scoop pumpkin flesh from the roasted pumpkin (or squash) and add to the pot. Cook everything together over medium to medium low heat for about 30 minutes
Remove the cinnamon sticks and add the heavy cream. Puree the soup with a stick blender until smooth and creamy. Garnish with mint, pumpkin seeds or sour cream and serve warm.