Clean the cauliflower, wash it and cut it into small florets. Cook in boiling salted water for 5-8 minutes. Drain and collect the stock. Wash the potatoes. Cook in boiling salted water for 15-20 minutes. Drain, peel and halve.
In the meantime, peel and finely dice the onions. Dice ham, grate cheese. Wash and chop the herbs. Heat the fat. Sauté onions, dust with flour and sauté. Deglaze with cream and 300 ml cauliflower stock. Bring to the boil while stirring constantly. Melt half the cheese in it. Stir in diced ham and herbs, except for something to sprinkle on top. Season to taste with salt and pepper. Put potatoes and cauliflower in an ovenproof dish. Pour sauce over it.
Melt half the cheese in it. Stir in diced ham and herbs, except for something to sprinkle on top. Season to taste with salt and pepper. Put potatoes and cauliflower in an ovenproof dish. Pour sauce over it. Sprinkle with remaining cheese. Bake in a preheated oven (electric: 200 °C/ gas: level 3) for about 20 minutes. Serve sprinkled with remaining herbs as desired