2 Granny Smith apples, cut into julienne strips, plus apple slices for garnish
2 ribs of celery, sliced thin diagonally
1/2 cups walnuts
1/2 cup mayonnaise
1/4 cup plain yogurt
1 teaspoon Dijon-style mustard
2 teaspoons sugar
1/4 cup vegetable oil
1/4 teaspoon salt, or to taste
1/4 cup red-wine vinegar
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.