1. Preheat the oven to 375ºF.
2. Peel and thinly slice the potatoes using a food processor or mandolin slicer.
3. Brush the bottom and sides of a 9-inch glass pie plate or skillet with butter. Arrange the potatoes to cover the bottom of the dish, overlapping the slices. Brush the layer with butter and season lightly. Continue layering the potato slices, brush each layer and seasoning lightly until all the potatoes have been used. Place a piece of parchment over the dish and weight it with a heavy lid or pan.
4. Bake the Pommes Anna for 20 minutes, then remove the weight and parchment and continue to bake until the potatoes are a rich golden brown and the potatoes yield when piece with a knife, about 50 minutes total. Cool for 10 minutes before inverting onto a platter or cutting board to serve, cut into wedges.
5. Pommes Anna can be prepared up to a day in advance and reheated in a 325ºF oven.