Finely chop the onions, the garlic and the chilli and add to a large pan with olive oil on medium heat. Cook for 5 minutes. Add the curry paste and mix well. Slice the red pepper, add it to the pan and cook for another 5 minutes.
Add the coconut milk, the mango chutney, the tomatoes (cored and roughly chopped) and some salt and let it cook for another 15 minutes. Add the sugar and mix well.
Add the spinach and the raw prawns. Let this cook for about 3 to 4 minutes until the prawns are cooked. Serve in individual bowls and finish with some chopped coriander and a squeeze of lime juice on each. Serve with naan bread or rice.