Prehehat oven to 400 degrees F.
In a shallow 1 1/2 quart baking dish, combine hash brown potatoes, butter and pepper. Press mixture into pan. Bake uncovered for 30 minutes.
Meanwhile, in a skillet brown beef; drain.
Stir in gravy mix, water and garlic salt, bring to a boil.
Reduce heat to medium and cook 5 minutes.
Stir in half of the cheese. Pour on top of potatoes.
Reduce oven to 350 degrees F. Bake, uncovered, for 15 minutes.
Sprinkle with remaining cheese and bake 5 minutes more.