Preparation

• In a very large bowl stir together the cabbage, the apple strips, the celery, and the walnuts.
  In a small bowl whisk together the mayonnaise, the yogurt, the mustard, the sugar, the oil, the salt, and the vinegar until the dressing is smooth.
  Pour the dressing over the cabbage mixture, and toss the slaw well. Chill the slaw, covered, for 2 hours.
  The slaw may be made 1 day in advance and kept covered and chilled.
  Serve the slaw topped with the apples slices.