Add cabbage, carrots, rutabaga and parsley to a large mixing bowl.
In the bowl of your small food processor, add all the ingredients for the vinaigrette and process until smooth and creamy.
Pour over the vegetables and mix well with your hand, taking care to massage the slaw well for a minute or two, to soften the veggies and get then to release some of their juices.
The slaw can be eaten immediately but will be much better after resting in the fridge for a couple of hours, or even overnight.
This salad will keep for 5-7 days in an airtight container.