Step 1

Heat the oven to 375° and coat a baking dish with butter. Arrange a rack in the middle of the oven and heat the oven to 375°F. Coat a 9x13-inch baking dish with the butter.

Step 2

Whisk together the wet ingredients. Place the cream soup, sour cream, and egg in a large bowl and whisk until smooth.

Step 3

Add the hash browns, onion, and half of the cheese. Add the hash browns, onions, and about half of the cheese and stir until well combined.

Step 4

Transfer the mixture to the baking dish and sprinkle with cheese. Pour the hash brown mixture into the baking dish and smooth into an even layer. Sprinkle with the remaining cheese.

Step 5

Bake for 45 minutes. Bake until the edges are crisp and the top is beginning to brown, about 45 minutes.

Step 6

Let cool for 10 minutes, then sprinkle with pepper. Remove the casserole from the oven and let cool for 10 minutes. Sprinkle with the black pepper, cut into squares, and serve hot.