Leeks cut into thin rings, pumpkin and potatoes into small cubes. Leeks fry in the butter. Add potatoes, pumpkin, milk, 250 ml water and add salt. Boil for half an hour with frequent stirring with a wooden spoon, so as not to burn the bottom. Then pureed in a blender, add to taste ground black pepper and more salt if necessary. Finally, add the cream and stir well.