Add celery, sweet potato or parsnip and potato and continue to cook for another 3 minutes. Stir in curry paste, red lentils and vegetable stock and bring to the boil. Cover, lower the heat and gently simmer for about 25-30 minutes or until the lentils are tender.

Add coconut milk, fresh coriander and the lime or lemon juice and season with salt and freshly ground black pepper to taste.

Transfer the mixture to a blender or food processor and whizz until smooth and then put the soup back into a clean saucepan to warm through and serve with pita bread (warmed in the toaster first) or bread of your choice.