step 1 Heat the oil in your largest pan, add the onion and fry for 3 mins to soften. Add the chicken and garlic, and cook until the chicken changes colour. step 2 Add the curry paste, coconut milk, stock, lime leaves and fish sauce, then simmer for 12 mins. Add the chopped onion tops, green beans and bamboo shoots and cook for 4-6 mins, until the beans are just tender. step 3 Meanwhile, put the lime juice and basil in a narrow jug and blitz with a hand blender to make a smooth green paste. Pour into the soup with the sliced spring onion and heat through. Serve with lime wedges for a light lunch or supper or as a make-ahead starter.