Peel and chop onion and garlic. Peel and wash the potatoes and slice or cut approx. 12 thin slices from one potato. Dice the rest roughly.
Heat the butter in a large pot. Sauté potato cubes, onion and garlic in it. Sprinkle with curry and sauté briefly. 3⁄4 Pour on l water and coconut milk. Bring to the boil, cover and simmer for about 15 minutes.
Clean and wash the spring onions. Cut diagonally into fine rings. Cut shrimps lengthwise at the back and remove the intestines. Rinse and dab dry. Heat 1 tablespoon of oil in a frying pan. Fry the potato slices for 1-2 minutes on each side.
Season with salt and take out. Heat 2 tablespoons of oil in a frying pan. Fry the prawns for 3-4 minutes. Season with salt and pepper.
Puree the soup with a hand blender only briefly. Season to taste with salt, pepper and ginger marmalade. Serve with prawns and potato chips. Sprinkle with spring onions.