1. In a large bowl combine cooked potatoes, 1/2 cup heavy cream, butter and salt and pepper to taste. Mix well with an electric mixer. If the mashed potatoes are too thick add milk until the desired consistency is reached.
2. Spoon potatoes into an 1 1/2 quart baking dish.
2. Beat cream until stiff. Fold cheese and chives into cream and season with pepper. Spread over potatoes.
3. Bake at 350 degrees F. (about 25 minutes) until lightly browned.