Lay the potatoes flat and slice thinly at regular intervals, not cutting through to the bottom of the potatoes. Season with salt and pepper or caraway seeds. Place the potatoes in a buttered, fireproof dish and dot with butter pieces. Bake for about 30 minutes in an oven preheated to 200c until crisp and cooked through. Sprinkle with grated cheese and return to oven for 5-10 minutes until the cheese has melted. Serve immediately.