Peel, wash and slice sweet potatoes and carrots. Peel and chop the onion. Heat 2 tablespoons of oil in a pot, fry the onion until transparent. Add carrots and potatoes, fry, dust with sugar, fry briefly.
Season with salt and pepper. Deglaze with broth, bring to the boil, cover and cook for about 25 minutes. In the meantime cut cabanossi lengthwise into very thin slices. Heat 1 tablespoon of oil in a frying pan, fry the cabanossi slices 1/2-1 minute on each side.
Remove from the pan. Remove the soup from the hotplate, puree it with a blender and pass it through a fine sieve. Stir in crème fraiche. Season again with salt, pepper and nutmeg. Fill the soup into small bowls and garnish with basil.
Cabanossichips to it.