Heat the oil to a frying temperature of 350 degrees F/180 degrees C.
Wash the flowers and dry thoroughly.
Put the egg and milk into a shallow dish and whisk to combine. Sprinkle with some salt and pepper. Sift the flour and cornstarch with a little more salt and pepper into another shallow dish.
Dip the zucchini blossoms into the egg wash, then dredge in the flour mixture. Plop into the hot oil and fry until golden. Drain on paper towels. Sprinkle with flaked sea salt and pepper and serve.