Preheat your oven to 425°F. Lightly butter an 8 or 10-inch oven-safe skillet.
Brush each layer with melted butter, then season it with kosher salt, freshly ground black pepper, dried thyme, and a sprinkle of Parmesan cheese before adding the next layer.
After adding the seasoning on the last layer, cover the skillet with aluminum foil and bake for 25 minutes. Then, take off the foil and bake for another 20 minutes, or until the potatoes are tender.