Preheat the oven to 400° F. Peel the potatoes. Then, cut them into thin, uniform slices. Wash them under running water and drain carefully on a linen cloth.
Cut the Brie into thin strips. Layer the potato slices in the baking dish, inserting strips of Brie between every layer. (Reserve some Brie for later). Pepper from the mill and salt, evenly.
Moisten with all or only a portion of the milk: it must be level with the highest potato. Top with the reserved strips of Brie and give a last turn from the pepper mill.
Bake for about 1 h, 20 min. After 40 min of baking, cover with aluminum foil, to avoid over browning. Serve healthy portions, along with roasted or grilled meat.