1Preheat an oven to 350 degrees F (175 degrees C). Grease a 9x13 inch baking dish.
2Slice potatoes with skins on into 1/4 inch thick slices. Place the potatoes into a large pot and cover with salted water. Bring to a boil over high heat, then reduce heat to medium-low, cover, and simmer until tender, 10 to 15 minutes. Drain and allow to steam dry for a minute or two.
3Mix together the mayonnaise, sour cream, onion and garlic powders, seasoned salt, pepper, bacon, onion, and American cheese in a bowl. Stir in the potato slices. Pour mixture into prepared baking dish. Sprinkle top with grated Parmesan cheese.
4Bake until bubbly and beginning to brown, 35 to 40 minutes.
Footnotes
Tip
Aluminum foil helps keep food moist, ensures it cooks evenly, keeps leftovers fresh, and makes clean-up easy.