Heat oil in a deep-fat fryer (or your largest pot on the hob) to at least 160 degrees. This will not work in an air fryer.
In a large bowl, add the flour. Gently whisk in most of the soda water. If the batter is too thick, add the rest. It should be able to coat the candy bar easily. Submerge each chocolate bar in the batter and carefully place it right into the hot oil either with your fingers or tongs, allowing it to fry for about 3 minutes or until the batter is puffed up and golden brown.
Use tongs to remove the battered chocolate bars and place them on a paper towel-lined plate. Enjoy immediately – if you decide to fry Bounty bars, those are great served with sliced pineapple.
