Preheat the oven to 375°F (190°C).

Grease a 9x13 inch oven-safe baking dish with 2 tablespoons of butter.

Peel and thinly slice 4 large potatoes using a sharp knife or mandoline for even thickness.

In a mixing bowl, whisk together 2 cups heavy cream, 2 cloves minced garlic, 1 teaspoon salt, 1/2 teaspoon black pepper, and 1/4 teaspoon nutmeg (optional).

Arrange a layer of sliced potatoes in the dish, overlapping slightly.

Pour half of the cream mixture over the potatoes, then sprinkle with half of the cheddar and Parmesan cheeses.

Repeat layering potatoes, cream mixture, cheddar cheese, and Parmesan cheese, finishing with a top layer of cheeses.

Cover the dish with foil and bake for 30 minutes at 375°F (190°C), then remove the foil and bake for an additional 15 minutes until the top is golden and bubbly.

Let the scalloped potatoes rest for 10 minutes before serving to allow them to set.