In a large mixing bowl, combine the shredded cabbage, carrots, and red onion.

In a separate bowl, whisk together the mayonnaise, buttermilk, apple cider vinegar, Dijon mustard, garlic powder, salt, and black pepper until smooth.

Pour the dressing over the slaw mixture and toss until well coated.

Fold in the crumbled bacon and blue cheese, and garnish with chopped parsley before serving.