For the fried pumpkin strips: heat oil in a saucepan and cook pumpkin slices until crispy brown. Drain on paper towels and sprinkle with salt.
For the soup: peel apple and onion and cut into small cubes. Heat butter in a saucepan, saute apples and onion briefly. Add pumpkin pulp and saute briefly as well. Add broth and simmer for about 20 minutes. Season with spices, add sour cream and sherry. Puree soup, season to taste and serve garnished with pumpkin strips.