Cook the cauliflower in boiling water for 2 mins. Tip into a colander, rinse under the cold tap, drain well and set aside.
Put the flour in a large bowl with a pinch of salt. Whisk the egg yolks and 175ml iced water together, then whisk into the flour with the oil to make a smooth batter. In a separate, clean bowl whisk the egg whites until stiff, then fold into the batter.
Heat the oil in a deep fryer or large wok to 190C. Coat some of the cauliflower in the batter then use a slotted spoon to carefully lift into the hot oil. Deep-fry the cauliflower for 2-3 mins until golden and puffy. Drain on kitchen towel and continue with the rest in batches. Sprinkle the cauliflower with salt and serve with a bowl of aÃ¯oli or mayonnaise.