Chop the garlic and cut the onion into small cubes.
Mix the ketchup with curry, salt and pepper in a bowl, add the lemon juice. Mix everything with the prawns and let stand for 15 minutes.
Heat some oil in a large pot or pan and add the sugar, carefully caramelize the sugar with a kitchen spoon until it turns nice and dark.
Now add the prawns and fry them until there is hardly any moisture. (Be careful when tipping the shrimp in - risk of splashing!).
Take the prawns out of the pot or pan and add the remaining ingredients to the pot. Lightly sear the vegetables and deglaze with 3/4 of the coconut milk. Cover and simmer for 5 minutes. Add the prawns and bring to the boil again. Season with salt and pepper and stir in the rest of the milk.
If you like it a little hotter, you can also cook a chilli pepper.