Wash the potatoes and cook in boiling water for about 20 minutes. Clean and wash the cauliflower and broccoli and divide into small florets. Cook cauliflower in boiling salted water for about 15 minutes, add broccoli after about 8 minutes.
Dab meat dry. Heat 2 tablespoons of oil in a frying pan. Fry the meat for 5-6 minutes, turning once, season with salt and pepper and remove. Heat the fat in a saucepan. Sprinkle flour over it, sweat it and add milk while stirring.
Bring to the boil, stir in stock and cheese, bring to the boil again. Drain potatoes, rinse, peel and halve. Heat 1 tablespoon of oil in a frying pan. Fry the potatoes for about 5 minutes while turning.
Meanwhile drain the cauliflower and broccoli. Divide the meat, potatoes and vegetables into 1 large or 4 small casseroles. Pour sauce over them. Grate the cheese and sprinkle over it. Bake in the preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) for 8-10 minutes.
Remove and possibly sprinkle with chopped parsley.