Preheat oven to 200° convection oven. Divide the cauliflower into florets, wash and blanch in salted water for 2 minutes, drain and rinse. Grease a baking dish and place the cauliflower in it. Heat the butter in a small saucepan and stir in the flour to make a roux. Pour in the soup and stir in. Add the diced ham. Simmer for about 10 minutes, then add the cream. Stir well and heat through. Season with salt and nutmeg. Pour the sauce over the cauliflower and sprinkle the cheese on top. Bake in the oven for 20 minutes and serve garnished with parsley.