As Beppino always loved to show me, both the female and the male zucchini produce flowers and they are easy to distinguish. The male flower is at the end of a long stalk, which is attached to the stem of the plant, whereas the female flower is attached to the courgette itself. Male flowers are easier to use in this recipe, as you can hold the stalk while you dip the flower in the batter, but both types taste equally delicious. In either case, check the flowers on the inside for bugs before starting, and always remove the pistil, which tastes bitter.
Separate the egg into 2 bowls, then cover and chill the egg white. Beat together the egg yolk, flour, and milk in a mixing bowl to make a smooth paste. In the other bowl, whisk the egg white until stiff, then fold it into the egg yolk batter.
Heat the oil in a large, deep frying pan over medium-high heat until a small cube of bread dropped into the oil sizzles instantly.
Meanwhile, if filling the flowers, tuck 1 teaspoon of the ricotta (or a piece of mozzarella) and a piece of anchovy into each zucchini flower. Holding the flowers by their stalks or ends, carefully dip them into the batter to coat thoroughly. If the flowers have been stuffed, fold down the petals of each flower and use the batter to secure the filling in place.
Working in batches if necessary to avoid overcrowding the pan, carefully lower the batter-coated flowers into the hot oil. Fry, turning frequently, until crisp and golden all over, for 3-4 minutes. Remove from the pan using a slotted spoon and drain well on kitchen paper. Serve the fried flowers sprinkled with a little salt.