Cut the potatoes and sweet potatoes into (wafer) thin slices and mix them well in the baking dish (the ratio of potatoes: sweet potatoes should be about the same everywhere).
Season the cream with salt and pepper and (depending on your taste) season with nutmeg or rosemary. Pour the cream mixture evenly over the potatoes, sprinkle with the cheese.
Bake at 200 ° C for approx. 50 minutes.
Something green goes with it, e.g., blanched broccoli, sugar peas