Cut the zucchini into about 2-inch (5 cm) disks, then cut each disk into 2-inch (5 cm) matchsticks. Place in a colander, sprinkle with sea salt, and leave for 30 minutes. Pat dry.
For the batter: Place the sifted flour into a medium bowl, make a well in the center, pour in the olive oil and stir slowly combining the flour into the oil. Loosen this paste with warm water, added slowly, stirring constantly, until you have a batter the consistency of double cream. Leave for a minimum of 45 minutes.
Heat the oil in a high-sided pan to about 400 degrees F (190 degrees C). Beat the egg whites until stiff and fold gently into the batter.
Dip the zucchini in the batter, then fry in batches in the hot oil until golden and crisp. Serve immediately.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Chefs Rose Gray and Ruth Rogers at River Cafe in London