Prepare the Potatoes: Preheat the oven to 400°F. Using a mandoline slicer (recommended) or sharp knife, slice the potatoes into very thin rounds about 1/8-inch in thickness. 

Assemble the Layers:  Brush an 8-inch oven-safe skillet with melted butter. Arrange a layer of potato slices in a circular, overlapping pattern. Brush the layer with melted butter and season with salt and pepper. If desired, sprinkle with a few thyme leaves. Repeat the layers until all the potatoes are used. 

Cook on the Stovetop: Place the skillet over medium heat for about 5 to 7 minutes, pressing gently with a spatula to help the layers stick together. You should have a golden brown crust on the bottom. 

Bake: Butter a sheet of foil and place it on the potatoes, buttered-side down.  Place a heavy pan or oven-safe weight on the foil to help compress the potatoes. Transfer the pommes Anna to the oven and bake for 30 minutes. Remove the foil and bake for 20 to 25 minutes longer or until the top is golden brown and crisp. 

Rest and Serve: Let the pommes Anna rest for 5 minutes, then loosen the edges with a spatula and carefully invert the potatoes onto a serving plate. Slice into wedges and serve hot. Enjoy!