Remove the outer leaves of the red and white cabbages, cut in half and remove the core. Finely shred the cabbages. You can use a mandolin, food processor or simply a sharp knife and a chopping board.
Peel the carrots and grate them using a box grater.
Finely chop the parsley.
Add the shredded cabbage, grated carrot and chopped parsley into a large mixing bowl.
Add the celery seeds, mayo, yoghurt, wholegrain mustard and apple cider vinegar.
Use clean hands to mix it all together until it is well combined.
Pile high in a serving bowl. Enjoy.