Peel, wash and quarter the potatoes. Pumpkin wash, quarter, core and cut into small pieces. Cook potatoes and pumpkin in boiling salted water for about 25 minutes
In the meantime soak the rolls in water. Peel and finely dice onions. Squeeze out the buns. Put minced meat, ground pork, squeezed out roll, half of the onions, mustard, 1 tsp salt and 1 tsp pepper in a mixing bowl and knead well. Form 8 equally sized meatballs from the minced meat mixture
Heat the oil in a coated pan, fry the meatballs on each side for about 3 minutes at medium heat, remove. In the meantime, clean the mushrooms, clean them and, depending on their size, halve them if necessary.
Sauté the mushrooms in the cooking fat while turning. Add remaining onions, fry briefly, season with salt and pepper. Dust with flour, sweat and gradually deglaze with stock and cream. Bring to the boil, simmer for 1-2 minutes, season with salt and pepper. Remove from the stove
Drain the potato-pumpkin puree. Let it steam a little. Add butter and mash very finely with a potato masher. Season with nutmeg and salt. Put the mushroom cream in an ovenproof dish, put the meatballs in it
Pour the potato and pumpkin vegetables into a piping bag with a large star-shaped spout. Spray a thick tuff on each meatball. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for 18-20 minutes. Cover the rest of the potato and pumpkin vegetables and put them in the oven
Meanwhile wash parsley, shake dry, pluck leaves from the stalks and chop finely. Remove the dish from the oven, sprinkle with parsley and garnish with parsley leaves as desired. Add the rest of the potato and pumpkin vegetables