Place half the basil and spinach in a blender fitted with a blade attachment and blitz so that there is room for the other ingredients. Now add the garlic, half walnuts, half Parmesan and blitz to blend. With motor still running pour in half the olive oil. The consistency must be chunky and coarse that will add texture to whatever you add it to. Repeat the process with the rest of the ingredients mentioned above. Now add the salt and lemon juice and mix. Taste and adjust seasonings if need be.