Step 1

Put the herbs, chillies, garlic, ginger and coconut milk in a blender and blend until completely smooth and bright green. (You can use a food processor, but a blender will make a smoother purée because it has four blades rather than two.)

Step 2

Pour the mixture into a medium saucepan and add the spices and 1 tsp salt. Bring to a simmer, add the squash and cook until soft – about 25 mins. Meanwhile, blanch the beans in boiling water, then drain and rinse in cold water – this keeps them perfectly cooked. Add them to the curry just before serving to warm them through. Serve with warm rice, extra coriander and chutney.