Peel the pumpkin, potatoes and onion and cut into large pieces. Heat some oil in a saucepan and fry the onions until golden. Add the pumpkin and potatoes, pour hot water over them, bring to the boil and simmer for 25 minutes. Then puree finely with the blender and add the vegetable stock.
Turn off the hotplate and mix the soup with the cream cheese. Season to taste with pepper and salt.