To make the batter, sift the flour and bicarbonate of soda into a medium bowl. Add the water and egg and briefly whisk until just combined but still lumpy (do not over mix). Place the bowl over a large bowl filled with iced water.
Add enough oil to a large saucepan to reach a depth of 5cm.
Heat to 190°C over medium-high heat.
Holding prawns by tails, dip six prawns, one at a time, into the batter to evenly coat. Shake off any excess.
Add prawns to the oil and cook for 3-4 minutes or until golden brown. Use a slotted spoon to transfer prawns to a tray lined with a paper towel.
Repeat, in three more batches, with the remaining batter and prawns, reheating the oil between batches.
Place the prawns on a serving platter and serve immediately with sauce of your choice.
