Preheat your oven to 350°F (175°C).

In a large mixing bowl, combine the cream of chicken soup, sour cream, melted butter, salt, and pepper.

Add the sliced potatoes and chopped onion to the bowl, stirring until well coated with the mixture.

Stir in 1 1/2 cups of the shredded cheddar cheese.

Transfer the potato mixture to a greased 9×13 inch baking dish.

Sprinkle the remaining 1/2 cup of cheddar cheese evenly over the top.

If using, mix the crushed cornflakes with 2 tablespoons of melted butter and sprinkle over the cheese.

Cover the dish with aluminum foil and bake in the preheated oven for 45 minutes.

Remove the foil and bake for an additional 15-20 minutes, or until the potatoes are tender and the top is golden brown.

Let it cool for a few minutes before serving.

For a bit of a kick, try adding some diced jalapeños or a pinch of cayenne pepper to the mix. If you have picky eaters, you can substitute the onion with onion powder for a milder flavor. For a vegetarian version, use cream of mushroom soup instead of cream of chicken. You can also add cooked bacon bits or diced ham for extra protein and flavor. Feel free to experiment with different cheeses like Monterey Jack or Swiss for a unique twist.