Dice the bread rolls. Heat 100 ml of milk and pour it over. Peel, wash and halve potatoes. Cook in boiling salted water for about 20 minutes. Peel and finely dice onion.
Knead minced meat, ground pork, onion, diced bread and 1 egg yolk. Season with pepper and a little salt. Clean the cauliflower, cut into large florets and wash. Cook in boiling salted water for about 10 minutes. Form approx. 12 small meatballs from the minced meat mixture.
Heat the oil in a frying pan, fry the meatballs on both sides for 2-3 minutes. Remove the cauliflower and measure 1/4 litre of vegetable water. Melt the fat in a pot and sauté the flour in it. Deglaze with vegetable water and 125 ml milk while stirring.
Season with salt, pepper and nutmeg. Mix 1 egg yolk with some sauce and fold in. Drain and mash the potatoes. Grease a large casserole dish. Pour in mashed potatoes. Spread cauliflower and meatballs on it and pour the sauce over it.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 10-15 minutes. Wash parsley, shake dry and chop coarsely. Take out the casserole and sprinkle parsley over it.