Cut the pumpkin into slices, remove seeds, peel, wash and cut into cubes. Peel onion and dice very finely. Peel, wash and dice potatoes and carrots. Heat the fat in a large pot and fry the onion until transparent.
Sprinkle sugar and let it caramelize. Add potatoes, carrots and pumpkin and steam for about 5 minutes. Season with salt, pepper and nutmeg. Add stock and simmer for 10 minutes. Puree soup and season again.
Stir in 100 g crème fraiche. Squeeze the sausage meat as small dumplings from the skin and let it stand in the soup for 10 minutes. Meanwhile roast pumpkin seeds in a pan without fat. Serve the pumpkin soup.
Serve with pumpkin seeds and remaining crème fraîche.