01 -
Preheat the oven to 400°F (200°C) and grease a ceramic baking dish.
02 -
Peel and thinly slice the potatoes using a mandoline or a sharp knife.
03 -
Melt butter in a large pot over medium heat. Add minced garlic and cook for 1 minute until fragrant.
04 -
Stir in flour and cook for 1 to 2 minutes to form a roux, ensuring it does not brown.
05 -
Gradually whisk in the heavy cream and cook for 5 minutes until the sauce thickens slightly.
06 -
Stir grated Parmesan cheese, fresh thyme, kosher salt, and black pepper into the sauce until smooth.
07 -
Add the sliced potatoes to the sauce and gently toss to evenly coat each slice.
08 -
Arrange the potato slices upright in the prepared baking dish and pour any remaining sauce over the top.
09 -
Sprinkle additional grated Parmesan on top to create a golden crust during baking.
10 -
Cover the dish with foil and bake for 30 minutes.
11 -
Remove the foil and continue baking for an additional 30 minutes until the potatoes are tender and the top is golden and bubbling.
12 -
Allow the dish to cool for 10 minutes before serving to let the sauce set.