Clean and wash the cauliflower, Romanesco and broccoli and cut them into florets. Peel, wash and cut carrots into pieces. Cook the cauliflower and Romanesco in boiling salted water for about 15 minutes. Add the broccoli and carrots 8 minutes before the end of the cooking time.
Grease a large casserole dish. Mix cream and milk, season with salt, pepper and nutmeg. Grate cheese. Add 1/3 to the cream. Drain the vegetables, let them drip off and put them into the casserole dish. Pour cream over it and sprinkle the remaining cheese over it.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 20-30 minutes. Garnish with parsley.