In this tutorial, we learn how to make cauliflower au gratin. First, cut the cauliflower into large florets, removing most of the stem to maximize the flavor. Wash out the vegetable thoroughly, then soak in vinegar and water overnight. After this, cook in boiling water for a few minutes, until it's slightly soft. Pour melted butter into a casserole dish, then drain your cauliflower and place it into the dish. Now, sprinkle parmesan cheese, bŽchamel sauce, and lots of cheese onto the cauliflower. After this, bake in the oven for around 20 minutes, or until the top is brown and the cheese is melted. After this, serve while hot and enjoy eating this delicious dish.