Preheat oven to 350°.
Combine turkey gravy, 1/2 cup cheese, onions, pepper, potatoes, and sour cream. Spoon into a shallow 1-quart casserole coated with cooking spray. Bake at 350° for 35 minutes. Sprinkle with 1/4 cup cheese and bacon. Bake an additional 5 minutes or until the cheese melts.