Wash the squash. Cut the bottom of the squash flat (just a little) so that it is stable. Cut the top and set aside. Using a spoon, remove the seeds and the filamentous pulp. Then, remove the flesh carefully without cutting through the skin. Wrap this emptied shell in aluminum foil and bake at 100°C (200°F).
In a pan, brown the squash flesh in a little butter. Add some vegetable broth (adjust depending on the water contained in the squash), then the curry, salt, pepper and cinnamon. Cook for 15 minutes over low heat.
Using a food processor, blend the soup until thin consistency. Add some crème fraiche, taste to adjust seasoning. Pour the soup in the shell, top with crème and sprinkle with smoked ham.