Preheat oven to 160ºC. Generously grease the bottom of an ovenproof pan or baking dish with 30 g of melted butter. In a medium saucepan over medium-low heat, add remaining butter and cheese cubes. Stir until cheese melts. Arrange potato slices in the pan overlapping each other, brushing with butter/cheese mixture. Season with salt and pepper as you go. Cover with greaseproof paper or lid and bake for 45 minutes to an hour. Test with a skewer to see if potatoes are tender.
At this point, serve immediately or refrigerate until ready to use. If preparing in advance, turn pommes out of the pan and with a sharp knife, cut into desired pieces. Warm in a 160ºC oven for 10 to 15 minutes.