01 -
Preheat your oven to 190°C (375°F).
02 -
Place the potato slices in a large bowl of cold water to prevent browning. Drain and pat them dry with a paper towel.
03 -
In a saucepan, combine the heavy cream, whole milk, minced garlic, dried thyme, butter, salt, and black pepper. Heat the mixture over medium heat until warmed through and butter is melted. Do not let it boil.
04 -
Grease a baking dish with butter or cooking spray. Place a layer of potato slices on the bottom of the dish, slightly overlapping them.
05 -
Sprinkle a portion of the grated Parmesan and Gruyere cheeses over the potato layer. Drizzle some of the cream mixture over the cheese.
06 -
Repeat the process of layering potatoes, cheese, and cream until all ingredients are used. Ensure the top layer has cheese and cream.
07 -
Cover the baking dish with aluminum foil and bake in the preheated oven for 45-50 minutes. Remove foil and continue baking for an additional 15-20 minutes, or until the top is golden brown and the potatoes are tender when pierced with a fork.
08 -
Remove the dish from the oven and let it cool slightly before serving. Garnish with chopped fresh parsley.