Select a head of cabbage that is reasonably solid and heavy for its size, with green outer leaves. Place the shredded cabbage and carrots in a salad bowl. In a separate bowl combine yogurt, buttermilk, mayonnaise, vinegar, sugar, Dijon mustard, celery seed, cayenne pepper, salt, and white pepper. Whisk until smooth, or prepare in a food processor or blender. Toss the cabbage and carrots with the dressing and allow to marinate for 2 to 3 hours or overnight. Serve chilled, garnished with shredded carrots.
Variation: The salad can be prepared with half green cabbage and half red cabbage.