Cook the cauliflower in salted boiling water. Divide into florets and place in a greased baking dish.
Melt the butter in a saucepan. Add the flour to the butter and let it sweat a little. Pour in the milk and cream and let thicken while stirring constantly over medium heat. Season to taste with nutmeg, salt and pepper.
Pour the sauce over the cauliflower. Sprinkle with grated cheese and bake in a preheated oven at 180 ° C top / bottom heat for about 20 - 30 minutes.
Tip: If you want, you can also add fried bacon cubes to the sauce.