Pumpkin thoroughly wash, clean, halve, core and roughly dice. Peel, wash and roughly cut the potatoes into pieces. Cover the potatoes and cook in little boiling salted water for about 20 minutes.
After 10 minutes add pumpkin to the potatoes and cook. Grate the parmesan. Wash sage, shake dry, pluck leaves from the stalks and chop, except for something to garnish. Warm up the milk.
Heat butter and sauté sage briefly in it. Drain potatoes and pumpkin and, except for some pumpkin for garnishing, press through a potato press. Add milk, cheese, except a little bit for sprinkling, and sage butter, except 1 tablespoon, and stir in.
Season to taste with salt and nutmeg. Arrange and garnish with pumpkin, sprinkle cheese strips, sprinkle sage butter and garnish with sage.