Cook the rice in salted water according to the instructions on the packet. Clean and wash the cauliflower, cut into small florets and cook for five minutes.
Heat the butter, sweat the flour in it and add the milk and stock, stirring constantly. Let simmer for five minutes as well. Season to taste with salt and pepper.
Preheat the oven to 200 ° C. Briefly fry the ham in a pan. Chop the parsley and stir into the sauce.
Layer the cauliflower, ham, rice and sauce alternately in a baking dish. Spread the processed cheese over it and bake the casserole for 30 minutes.