Roughly chop the parsley. If the leaves are small, I like to leave them whole. Make the herb dressing by putting the basil leaves and stems and parsley leaves into a food processor or blender, with the chilli (halved and seeds removed), shelled walnuts, olive oil and a pinch of sea salt, and processing to a coarse green paste. Taste the paste for seasoning and add salt and lemon juice as necessary.