500ml (2 cups)malt vinegar80 gmsea salt2 tbspcaster sugar4onions, thinly sliced into rounds50gmrice flour, plus extra for dustingVegetable oil, for deep-fryingBatter200 gmrice flour105 gmself-raising flour5 gmbaking powder170 mlvodka (preferably with 37% alcohol)20 gmhoney275 mlbeer, such as draught beer
Bring vinegar, salt and sugar to the boil in a saucepan. Remove tiny rings from centres of onion (reserve for another use). Separate onion into individual rings and simmer in 2 batches in vinegar mixture until just softened (1 minute). Transfer to a bowl with a slotted spoon.
For batter, combine flours and baking powder in a bowl. Whisk vodka and honey together in a jug, then add to flours along with beer and whisk until batter has the consistency of heavy cream. If it becomes too thick add a little more beer.
Heat oil in a deep-fryer or large saucepan to 180C. Dust onion rings with rice flour, coat in batter and, in batches, carefully lower into the oil so the batter puffs up before the ring has a chance to sink. Deep-fry until light golden brown and crisp (1-2 minutes; be careful, hot oil may spit), then season with salt and serve.