Prepare the vegetables. After removing the tough cores from both cabbages, slice them as thinly as you can — aim for ribbons about 2–3mm wide. The shreds should look delicate and almost translucent at the edges. Grate or julienne the carrots into fine matchsticks so they blend with the cabbage rather than clumping. Slice the red onion into whisper-thin rings; you should be able to see light through them.

Salt and rest the cabbage. Place all the sliced cabbage and onion into a colander set over a bowl. Sprinkle over the teaspoon of salt, then use your hands to toss and gently massage the salt into the leaves for about one minute. You will notice the cabbage starting to look wet and glossy. Leave it to sit for 30 minutes. During this time, the salt draws out the natural water, and the cabbage will soften slightly while keeping its crunch.

Rinse and dry thoroughly. After 30 minutes, rinse the cabbage and onion under cold running water to remove the excess salt. Shake the colander well, then tip everything onto a clean tea towel. Roll the towel up and twist it firmly over the sink to squeeze out as much moisture as possible. The vegetables should feel dry to the touch, not wet. Transfer them to a large bowl, add the grated carrots, and toss to combine.

Make the dressing. In a small jar, combine the mayonnaise, yogurt, cider vinegar, lemon juice, Dijon mustard, celery seeds, black pepper, and honey. Screw the lid on tightly and shake vigorously for 20 seconds until the dressing is pale, creamy, and fully emulsified. It should have the texture of a thin custard — smooth and pourable.

Dress and rest again. Pour the dressing over the dried vegetables and toss thoroughly with your salad servers or clean hands, ensuring every strand is lightly coated. The coleslaw will look glossy but not drenched. Cover the bowl with cling film and refrigerate for at least 30 minutes, or up to two hours. This resting time allows the flavours to meld and the cabbage to absorb the dressing without becoming soggy.

Finish and serve. Just before serving, sprinkle over the chopped parsley and give the coleslaw one final gentle toss. Taste and adjust seasoning with a tiny pinch of salt if needed. To plate, use your salad servers to lift the slaw from the bottom, allowing any excess dressing to drip back into the bowl, then pile it high in a shallow serving dish. The finished salad should be a tangle of colourful ribbons, each strand distinct and glistening.