Peel the potatoes and slice them. Put the cauliflower, broccoli and the potatoes in boiling salted water and cook for about 10 minutes.
In the meantime, whisk the sour and sweet cream with the egg and season with salt, pepper and a pinch of nutmeg. Take the vegetables out of the pot and spread them with the ham in a baking dish. Pour the cream sauce over it and sprinkle with grated cheese. Baked in the oven for about 15 minutes.