4 c. mashed potatoes, freshly cooked
1 (8 oz.) pkg. cream cheese
1 egg
1/3 c. onion, finely chopped
1/3 c. shredded Cheddar cheese
Salt and pepper to taste

Mix all ingredients well, using an electric mixer. Turn into 1 1/2 quart baking dish. Bake, uncovered, at 350 degrees for approximately 45 minutes or until top is nicely browned.