Possibly defrost the prawns. Boil up just under 1/2 l water and broth. Wash the prawns and simmer in it in 3 portions for 1-2 minutes each. Lift out. Put stock and shrimps aside
Peel and finely dice the onions, garlic and ginger. Cut the chilli lengthwise, remove seeds, wash and chop. Fry everything in hot oil. Sweat curry and flour briefly. Stir in broth and coconut milk, bring to the boil. Season with salt and pepper
Clean the lemon grass, cut in half lengthwise and add to the curry. Simmer covered at low heat for about 10 minutes, stirring from time to time.
Clean, wash and finely chop the spring onions. Remove the lemon grass. Heat prawns and spring onions in curry. Season to taste. Wash and pluck the coriander. Sprinkle over. Serve with: Basmati rice or baguette