Making Potatoes Au Gratin is a simple yet rewarding culinary adventure. Follow these easy steps to achieve the perfect results:

1. Preheat Oven: Preheat your oven to 375°F (190°C). Greasing a 9×13-inch baking dish with butter will help prevent sticking.
2. Prepare Potatoes: Wash and peel the potatoes, then slice them thinly (about 1/8 inch thick). You can use a mandoline for uniform slices, ensuring even cooking.
3. Heat Cream: In a saucepan, combine the heavy cream, minced garlic, salt, pepper, and nutmeg. Heat over medium until hot but not boiling.
4. Layer Potatoes: Arrange half of the sliced potatoes in the greased baking dish, overlapping slightly. Pour half of the cream mixture over the top.
5. Add Cheese: Sprinkle half of the cheddar and Gruyère cheeses over the potatoes. Repeat with the remaining potatoes, cream, and cheeses.
6. Top It Off: Dot the top layer with butter and sprinkle the grated Parmesan cheese evenly over the dish.
7. Cover and Bake: Cover the baking dish with aluminum foil (to prevent over-browning) and bake for 45 minutes.
8. Uncover and Continue Baking: Remove the foil and bake for an additional 15-20 minutes, or until the top is golden brown and bubbling.
9. Cool: Once baked, allow the dish to cool for 10-15 minutes. This step helps the layers to set properly.
10. Garnish: If desired, sprinkle chopped fresh parsley on top for added flavor and a touch of color.

These steps will guide you in creating a dish that not only pleases the palate but also impresses everyone at the table.