Let’s dive into the cooking process and bring these delicious potatoes to life:

1. Preheat your oven to 375°F (190°C) and grease a baking dish with 1 tablespoon of butter.
2. In a saucepan, combine the heavy cream, milk, minced garlic, salt, pepper, and nutmeg. Heat over medium until just simmering, stirring occasionally, then remove from heat.
3. Layer half of the sliced potatoes in the prepared baking dish. Sprinkle half of the Parmesan and cheddar cheese over the potatoes.
4. Pour half of the cream mixture over the cheese-topped potatoes, ensuring even distribution.
5. Repeat the layering with the remaining potatoes, cheese, and cream mixture.
6. Dot the top with the remaining butter and sprinkle with breadcrumbs if using.
7. Bake in the preheated oven for 45-50 minutes, or until the top is golden brown and the potatoes are tender when pierced with a fork.
8. Let the dish rest for 5-10 minutes before serving. Garnish with freshly chopped parsley for a splash of color and freshness.

Cooking alongside my abuela taught me to trust my senses, so feel free to adjust the seasoning to your liking. Remember, the kitchen is your playground!