While you can make it with pesto from a jar, the difference when you use the "fresh" stuff in a tub that you can find in chiller cabinets in the supermarkets is astonishing. I think soup tastes better made in a blender rather than a food processor, and it's best to use a blender which has a central plug in the lid that you can remove to stop the pressure building up - which, in turn, prevents you getting soup all over you or your walls.
This recipe evokes all the feelings of Spring-time. For other Spring recipe inspiration try Nigella's other delicious Spring food ideas.
Recipe posted by Nigella