The ingredients are basic and can be found in most store cupboards. This guide will make enough for 2 or 3 portions.
Firstly start by nipping the end off of the onions and peeling them whole.
Cut the whole onion into medium slices, if they're too thin they will burn quickly and if they're too thick they won't cook all the way through.
With your thumb push the centre of the onion out to release the rings.
Pop into a colander and lightly salt.
To make the batter, weigh out the flour
Beat the egg separately.
In a bowl, mix the water, egg and flour. Add the salt and baking soda.
Whisk until well incorporated, there should be a light layer of bubbles on top of the batter when finished.
Fire up your fryer or heat up the oil if you are using a pan.
Test the oil by dipping a piece of raw onion into the oil, it should hiss and spit when it's ready.
Dip the rings into the batter and cover.
Gently place the battered rings into the oil and cook for 4-6 minutes. Stirring and turning every minute or so.
Remove the onion rings from the oil and place on a piece of tissue paper to let dry.
Once the rings have cooled and the oil dripped off, dip them one more time back into the batter and then back into the oil.
After a few minutes the rings should puff up and turn golden brown. Remove from the oil drain onto a piece of kitchen roll.
Season with a little salt and enjoy.