Heat a drizzle of vegetable oil in a large pot over a medium heat and add the curry paste. Fry for a couple of minutes until fragrant then add the pepper, spring onion, coconut milk, lime zest and juice, sugar and fish sauce.
Bring to a simmer then add the prawns and cook for a couple more minutes until the prawns are pink and cooked through. Serve with rice or noodles and chopped with coriander.
Nutrition information is an estimate and will vary depending on the exact ingredients used.