Step 1

For the Slaw Mix: Combine cabbage, onion, carrot, and parsley in a large bowl, leaving plenty of room to toss (you may have to use two large bowls if your bowls are not large enough). Sprinkle with sugar and salt and toss to combine. Let rest five minutes, then transfer to a large colander and rinse thoroughly under cold running water.

Step 2

Transfer rinsed mixture to a salad spinner and spin dry. Alternatively, transfer to a large rimmed baking sheet lined with a triple layer of paper towels or a clean kitchen towel and blot mixture dry with more paper towels. Return to large bowl and set aside.

Step 3

For the Dressing: Combine mayonnaise, vinegar, mustard, black pepper, and sugar in a medium bowl and whisk until homogenous.

Step 4

Pour dressing over cabbage mixture and toss to coat. Taste and adjust seasoning with more salt, pepper, sugar, and/or vinegar if desired.