Peel and roughly dice the onion. Peel, wash and cut the potatoes into small pieces. Clean, wash and chop the fennel. Chop half of the fennel greens finely. Heat 1 tablespoon of oil in a pot.
Sauté the potatoes, fennel and onion. Add stock and broth. Bring to the boil, cover and cook for about 20 minutes. Cut the mango from the stone. Peel and chop the flesh. Peel prawns, except for the tail fin, and remove the intestines.
Wash the shrimps and pat them dry. Heat 1 tablespoon of oil in a frying pan. Fry the prawns for about 4 minutes, turning them over and season with salt and pepper. Take them out and let them drip off on kitchen paper.
Pour cream into the soup. Puree the soup finely. Stir the chopped fennel greens into the soup, season with salt and pepper. Arrange the soup in plates. Add scampi and mango cubes to the soup and garnish with fennel green.