Cut the onions into 1-inch thick slices.
2 onions large
In a large bowl, combine flour, baking powder, salt, paprika, egg, and milk to form a thick batter.
1 ¼ cups all-purpose flour, 1 teaspoon baking powder, 1 teaspoon salt, 1 teaspoon paprika, 1 egg, 1 cup milk
Transfer them to a tray and sprinkle with some breadcrumbs (optional).
Breadcrumbs as needed
Heat the oil to medium-high (should be around 180ºC (350°F), you can test it by throwing a piece of bread or batter in, it should float and start bubbling softly - if it sinks it’s too cool, if it bubbles a lot it’s too hot).
Frying oil
Add the onion rings in batches and fry in both sides until they are golden brown. Transfer to a paper-lined tray to remove excessive grease.
Serve with herby mayo, BBQ, or spiced ketchup.