For pumpkin puree, cut pumpkin into quarters, remove seeds. Bake at 350 degrees until soft, about 1 hour.
For soup, melt butter in large saucepan over medium high hear. Add onions and cook until softened, about 5 minutes. Add garlic, red curry paste, cayenne, curry and coriander. Cook and stir for 1 minute. Add vegetable broth and milk. Peel pumpkin and add flesh to pot. Bring to boil and reduce heat. Simmer for 25 minutes, stirring to break up pumpkin.
Transfer soup in batches to blender; don't overload the blender. Cover tightly and blend until smooth. Return soup to saucepan. With the soup on low heat, add brown sugar and cream. Adjust seasonings to taste and serve.
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