Peel and slice the potatoes and onion into nice thin slices. Grease a casserole dish and layer the potato, onion and cheese in it. Pour over the stock and dot with butter. Sprinkle paprika on top. Season with salt, pepper and garlic powder to taste, if desired.
Cover the casserole and bake at 350*F. for 45 minutes. Take The lid off and cook 15 minutes more.