These Easy Potatoes au Gratin (otherwise known as Dauphinoise) are a French classic. But don't let that scare you. They are so easy to make and comforting with its layers of sliced potatoes, cream, and cheese!
Preheat oven to 425°F. Grease a 9x13 baking dish with butter.
Place ½ the sliced potatoes in the prepared baking dish. Sprinkle with ½ of the garlic powder, salt, and pepper. Sprinkle with ½ of the shredded cheddar. Place the slices of provolone on top of the cheddar and sprinkle with ½ of the shredded Parmesan.
Top with remaining sliced potatoes. Sprinkle potatoes with remaining garlic, salt, and pepper. Sprinkle with remaining cheeses. Pour cream all over the potatoes. Cover with foil and bake for 50 minutes. Remove foil and bake for 10 minutes or utnil cheese is lightly browned on top. Remove from oven and let stand for 10 minutes before serving.