Step by step
In a large saucepan heat the oil over a medium heat and gently cook the celery and pepper for 4-5 minutes with the lid on, stirring occasionally, until it starts to soften.
Add the garlic, chilli and cayenne and stir. After a minute stir in the tomatoes and spring onions. Cook for 3-4 minutes then add the coconut milk and stock. Bring to the boil.
Add the prawns and season. Simmer gently for 5-6 mins until the prawns are cooked. Check the seasoning then divide the stew between two bowls and top with coriander and a squeeze of lemon.