Preheat the oven to 350 degrees F and spray a 9X13 baking pan with a non stick cooking spray.
Brown the ground beef and drain off any excess grease.
Then in a large mixing bowl, stir together the browned ground beef, hashbrowns, chopped onions, milk, cream of mushroom soup, pepper and half of the cheese (1 cup).
Pour this mixture into the baking pan.
Bake for 45 minutes to 1 hour until the hash browns are golden brown and tender.
Top the casserole with the remaining cheese. Bake for 5 more minutes until the cheese is melted.
Let the casserole rest at room temperature for 5 minutes and then the casserole is ready to serve and enjoy!