Combine the cubed pumpkin, milk and chicken stock in a saucepan. Season with salt, pepper, curry powder, celery salt, cinnamon and nutmeg. Bring to a boil then reduce heat to low and simmer for about 30 minutes until squash is tender stirring frequently to prevent the milk from scorching.
Add 1/2 the prawns and 1/2 the pears to the soup then bring to a boil. Cook for 5 minutes or until the prawns are opaque.
Transfer the soup to a blender or food processor then blend until smooth. Return to the saucepan and bring to a simmer over medium-low heat.
Add the remaining prawns and remaining pears to the soup then simmer for another 5 minutes or until prawns is opaque. Stir in sherry and remove from heat.
Ladle into bowls and garnish with a light sprinkle of cinnamon or nutmeg.