Peel the onions and chop them into slices, around 1cm thick. Gently separate them into rings.
Mix the flour, baking powder, paprika and salt together in a large bowl. Mix the lager into the flour mix using a whisk - I find it best to do this in 3-4 batches so it doesn’t fizz up everywhere! Mix well until it’s lump-free then leave to stand at room temperature for 10-15 minutes.
When ready, fill a pan with approximately 3 inches of oil (approx 1 litre depending on pan size) and heat to 180C (I highly recommend using a thermometer. However if you don’t have one, you can drop a tiny bit of batter into the oil. When ready it should sizzle with a few bubbles - if it does nothing, it’s not hot enough. If it violently sizzles, it’s too hot. But a thermometer is the best way!!)
Working quickly, dip 4-5 onion rings into the batter, turning to coat completely, then straight into the oil. You don’t want to crowd them in the pan! Fry for approx 45 seconds, then flip and fry for another 45 seconds until golden brown all over. They should be golden brown on each side.
Remove from the oil using a slotted spoon and onto a plate lined with some sheets of paper kitchen towel to absorb the oil.
Continue to fry the onion rings in batches - ensure you stir the batter each time (the flour will settle on the bottom otherwise) and keep checking the oil temperature. Once all the onion rings are cooked, serve them and enjoy!
Video
Notes
Any leftovers can be stored in the fridge or frozen and reheated to serve. I recommend reheating in the air fryer or oven to maintain crispiness!