Peel and wash the potatoes and cut them into thin slices. Pumpkin clean, wash, quarter, core and cut into slices about 0.5 cm thick.
Peel and finely chop the garlic. Bring cream and garlic to the boil and season vigorously with salt, pepper and nutmeg. Layer potatoes first, then the pumpkin in 4 casserole dishes (each approx. 12 cm Ø), possibly spread with fat.
Pour about 1/4 cream over each and sprinkle with parmesan. Bake in the preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer) for approx. 30 minutes. Wash parsley
Pluck off leaves and chop finely. Remove gratin from the oven and sprinkle with parsley.