Step 1

Preheat the oven to 350 degrees F.

Step 2

Lightly coat a 9x13-inch baking dish with nonstick cooking spray.

Step 3

In a large bowl, add the shredded potatoes, the soup, the cheddar cheese, the sour cream, 1/4 cup of the butter, the milk, the garlic powder, and the onion powder and mix until well combined.

Step 4

Evenly spread the potato mixture on the bottom of the prepared baking dish.

Step 5

In a medium bowl, add the cereal and gently break it up, then add the remaining butter and mix well.

Step 6

Evenly sprinkle the cornflake mixture over the potato mixture.

Step 7

Bake the casserole, uncovered, until it is bubbly and the topping is golden, about 35-40 minutes.

Step 8

Plate and serve.