Preheat your oven to 180°C (350°F) and lightly butter your 8-inch baking dish.
Using a mandoline slicer, slice the russet potatoes very thin, about 3 mm thick, keeping the slices uniform for even cooking.
In a saucepan, melt the butter over medium heat until it begins to foam and smell fragrant.
Add the minced garlic to the butter and cook for about 30 seconds until it becomes fragrant and slightly golden.
Pour in the heavy cream, add a pinch of nutmeg and salt, then simmer gently until the mixture thickens slightly and you smell a rich aroma, about 3-4 minutes.
Arrange a layer of potato slices in the prepared baking dish, overlapping slightly, creating an even layer across the bottom.
Pour a portion of the warm cream mixture over the potatoes, ensuring each layer is coated evenly.
Sprinkle a third of the grated cheddar and Gruyère cheeses over the layer, distributing evenly for a cheesy top.
Repeat the layering process: add another layer of potatoes, pour over the cream, and sprinkle with cheese, until all ingredients are used, finishing with a cheese layer on top.
Cover the dish with foil and bake in the preheated oven for 45-50 minutes, until the potatoes are tender and the top is bubbling.
Remove the foil and continue baking for an additional 10-15 minutes, until the top is golden brown and crispy.
Let the dish rest for about 10 minutes. This helps the layers set and makes slicing easier.
Serve warm, enjoying the tender layers, cheesy richness, and slightly smoky crust—a perfect comfort dish with a crispy top and creamy interior.
