Tian de Courgettes

‘Tian’ is a type of gratin dish, which also gives its name to the food cooked in it. It can be prepared with any vegetable; some favourites are spinach, leaves of Swiss chard and wild asparagus. Sometimes mixtures of vegetables are used: green peas and artichokes, spinach and pumpkin. For this recipe, the courgette/zucchini flowers are often included.