Preheat the oven to 350 degrees F. In a large skillet add the breakfast sausage and cook while breaking up into chunks with a spatula until no longer pink and fully cooked.
Remove from the skillet using a slotted spoon.
Add the hash browns to the skillet and cook until lightly browned. Place the hash browns onto the bottom of a lightly greased 9×13 inch baking dish. Top with sausage and cheese.
Whisk together eggs, salt, pepper, and milk. Pour the egg mixture over the ingredients in the baking dish.
Place into the oven and bake for 40 minutes or until the casserole is golden brown and set.