Onion rings are one of the cheapest snacks you can make at home: two large onions, a little flour and oil. Golden and crispy outside, soft and slightly sweet inside. And that is exactly why they're so easy to ruin - one mistake is enough for them to end up as greasy, soggy rings.

Their roots go back to early 19th-century Britain, but they became hugely popular in the US in the 20th century, along with burger joints, roadside diners and fast food. There are two main methods, and both work if you follow a few rules.

Method 1: in a light batter with sparkling water (serves 4)

• 2 large onions, sweet or mild
• 120 g plain flour
• 60 g cornflour
• 1 teaspoon baking powder
• 250 ml ice-cold sparkling water
• 1 teaspoon salt and black pepper
• plenty of vegetable oil for frying

Peel the onions and slice them crosswise into rounds about half a centimetre thick, then carefully separate the layers into rings. Mix the flour, cornflour, baking powder, salt and pepper, then gradually add the cold sparkling water until you have a smooth batter - thick, but still runny. Dip the rings so they're completely coated and fry them in oil heated to 175-180 degrees until golden. Don't overcrowd the pan. Drain them on a rack or on kitchen paper and eat them straight away.

Method 2: in a panko crust (serves 4)

• 2 large sweet onions
• 100 g plain flour
• 2 eggs and 150 ml milk
• 180 g panko (Japanese breadcrumbs)
• 1 teaspoon salt, half a teaspoon black pepper
• half a teaspoon garlic powder and half a teaspoon sweet paprika
• a pinch of cayenne or chilli, optional
• mild-flavoured oil for frying

Set out three plates: flour with salt and pepper in the first, eggs beaten with milk in the second, and panko with salt, garlic, paprika and, if you like, cayenne in the third. Each ring goes first through the flour (shake off the excess), then the egg, then the panko, pressing lightly. For a thicker crust, repeat the last two steps. Leave the rings on a rack in the fridge for 15-20 minutes - almost everyone skips that rest, and it's exactly what keeps the crust in place. Fry them at 175-180 degrees, 2-3 minutes per side, until deep golden, and salt them immediately while they're hot.

The rules that make the difference

Use large, firm, mild onions. There has to be plenty of oil, and it has to stay between 175 and 180 degrees - which is only possible if you fry in batches, a few rings at a time. Too many rings in the pan drop the temperature, and instead of sealing, they start soaking up oil. Draining on a rack beats a pile on paper, because the air circulates and the underside doesn't go soft.

In an air fryer, the panko version works better: spray the rings with a little oil and cook them at 190 degrees for 8-12 minutes, turning them halfway. The light batter version is harder there, because the batter drips off before it sets.

For dipping, the choice is wide: barbecue sauce, ketchup, garlic mayo, ranch, honey mustard, sriracha mayo or sweet chilli sauce. In Macedonia, onions usually end up in a salad or in tavče gravče, the baked bean dish. Maybe it's time they got the lead role at least once.