In a large mixing bowl, combine thin slices of potatoes, buttermilk, 1 cup of Parmesan cheese and 1 packet of Hidden Valley Ranch seasoning mix. Toss to coat. Set aside.
In a large skillet, cook bacon to crispy. Remove onto a paper towel lined plate.
To bacon grease, add shredded cabbage and cook until wilted. Remove from heat, add salt and pepper and 3/4 of the bacon and 3/4 of chopped chives. Reserve the rest for garnish.Toss everything together.
Arrange one layer of potato slices in the prepared casserole dish. Sprinkle with Parmesan cheese. Repeat one more layer.
Arrange cabbage and bacon layer over potatoes. Top with two more layers of potato slices. Add about 1/2 of the buttermilk mixture, enough to slightly cover the last potato layer. Top with Parmesan cheese.
Cover dish with aluminum foil and bake for 1 hour.
Remove the foil and bake 30 more minutes.
Let casserole cool for 15 minutes before serving.
Garnish with remaining bacon and chives and serve.