Cut the pumpkin flesh into small pieces, and simmer in the water until quite soft, adding extra water if necessary. Push all through a fine sieve.
Return the resulting puree to the rinsed saucepan or casserole, thin with the chicken or vegetable stock ( or water ) and reheat, adding the cream gradually and seasoning with salt.
To serve the soup, have ready 4 wide ovenproof soup bowls, and cut the cheese into dice. Heat the oven, pour the hot soup into the bowls, scatter cheese onto each, transfer to the oven and heat until the cheese melts.