Place the potatoes in a large pot, and fill with enough water to cover. Bring to a boil, and cook until fork tender, about 15 minutes. Drain, and cut into chunks, leaving the skins on.
Preheat the oven to 375 degrees F (190 degrees C). Meanwhile, fry the bacon in a large skillet until browned and crisp. Drain, and set aside.
Place the potatoes in a greased 9x13 inch baking dish. In a medium bowl, stir together the sour cream, Ranch dressing, parsley, and 3/4 cup Cheddar cheese. Crumble in the bacon and stir. Pour over the potatoes in the baking dish. In a another bowl, mix together the cornflake crumbs, melted butter and remaining cheese. Sprinkle evenly over the top of the casserole.
Bake for 40 to 45 minutes in the preheated oven, or until the top of the casserole is browned and crisp.