Wash and peel the potatoes.
With a mandolin or a food processor, cut the potatoes into 3mm thick slices.
Preheat the oven to 180°C.
Boiled milk with nutmeg and chopped clove of garlic in a large saucepan.
Salt and add pepper.
From the first shivers, add potatoes and cook for about 10 minutes over medium heat.
Pour all preparation into a large gratin dish, with the potatoes on top.
Pour the cream oven the potatoes, sprinkle with cold butter shavings and add a few sprigs of thyme.
Drop for an hour and let stand a few minutes before serving.