Cook the vegetables in boiling salted water, first cook the cauliflower, a little later the carrots and then the broccoli until al dente, then drain. Put the vegetables in the tin, sprinkle the boiled ham on top.
Melt the butter in a saucepan, add the flour and sweat until lightly, pour in the cream and milk, stir constantly, simmer for about 3 minutes, stir in the cheese and season (salt, pepper and nutmeg). Pour the cheese sauce over the vegetables and place in the preheated oven for 15 minutes at 200 °.