Thinly slice the zucchini into discs: the thinner they are, the crisper they will be when fried. Place in a large bowl of iced water for at least 30 minutes. Drain in a colander and dry well.
Heat the oil 180°C/350°F. Fry the zucchini in batches until light brown and crisp, then remove immediately and place on kitchen paper to drain. Avoid putting too many in the oil at one time, as thi