1. Wash the elderflowers under slow-running water, then drain them thoroughly on a tea-towel.
2. Sift the flour into a bowl. Separate the egg. Beat the yolk with the flour, adding sufficient pale ale to make a thick batter. Cover and leave the batter to stand for 30 minutes. Whisk the egg white with the salt until it is stiff.
3. Heat the oil in a deep-fryer or large saucepan to 180°c (350°f). Stir the batter thoroughly and fold in the egg white. Dip the elderflowers one after the other in the batter and plunge into the hot fat. Fry each flower for 4-6 minutes and drain on absorbent paper.
4. Keep the cooked blossoms hot in the oven until all are cooked. Mix the cinnamon into the sugar and sprinkle the mixture over the blossoms.