Preheat the oven to 400°F.
Generously coat a 9x13-inch baking dish with nonstick cooking spray.
Set the prepared baking dish aside.
In a large mixing bowl, add the undiluted cream of chicken soup.
Add the sour cream to the bowl.
Add the dry ranch dressing mix, onion powder, freshly cracked black pepper, and kosher salt.
Whisk the mixture until smooth and fully combined.
Add the frozen hash browns to the bowl.
Add 1 cup of the cooked crumbled bacon.
Add 3 cups of the shredded sharp cheddar cheese.
Using a large wooden spoon, stir the mixture until the hash browns, bacon, cheese, and sauce are completely combined.
Transfer the potato mixture to the prepared baking dish.
Spread the mixture evenly in the dish.
Sprinkle the remaining 1 cup of shredded sharp cheddar cheese evenly over the top.
Sprinkle the remaining 1/2 cup of cooked crumbled bacon evenly over the cheese.
Place the baking dish in the preheated oven.
Bake for 50 minutes, or until the casserole is hot, bubbly, and the cheese is fully melted.
Remove the casserole from the oven.
Sprinkle the chopped parsley evenly over the top, if using.
Serve hot.