How to make
Tear the broccoli and the cauliflower into florets, then boil them for 5 minutes. You can also blanch them.
Then, pour them into a buttered baking dish and mix with the chopped onion and garlic. In a bowl, combine the milk, parsley, mayonnaise, parmesan, mustard, black pepper and salt to taste.
Stir well and pour the mixture over the vegetables. Sprinkle with breadcrumbs and put to bake for about 30 minutes in a preheated 350°F (175 °C) oven.