Peel the onions and slice into 1/4 to 1/2 inch rings. Separate into individual rings and set aside. If rings are large, split them into 2-3 rings each so sizes are even.

Make batter

In a large bowl whisk together the all-purpose flour, cornstarch, baking powder, salt, black pepper, paprika, and garlic powder. In a separate small bowl whisk the egg, then add cold sparkling water (or cold beer) to the egg and mix. Pour the wet into the dry and whisk until just combined; a few lumps are fine. Batter should be thick but still pourable. If using breadcrumbs for extra crunch, spread them on a plate now.

Heat oil

Pour vegetable oil into a deep heavy pot or deep fryer to a depth of about 2-3 inches. Heat to 350°F (175°C). If you don't have a thermometer, test by dropping a small bit of batter — it should sizzle and rise to the surface steadily.

Coat and fry

Working in small batches (6-8 rings at a time), gently pat excess moisture from onion rings with a paper towel, dip each ring into the batter to coat completely, allow excess batter to drip off, then optionally dredge in breadcrumbs for extra crunch. Carefully lower rings into hot oil, avoid overcrowding. Fry until golden brown, 2.5–3.5 minutes, turning once if needed. Use a slotted spoon to transfer to a wire rack set over a baking sheet or paper towels to drain. Immediately season with a light sprinkle of salt while still hot. Repeat with remaining rings, maintaining oil temperature between 340–360°F (170–180°C).

Keep warm

If making large quantities, keep finished rings in a single layer in a 200°F (95°C) oven on a wire rack to stay crisp while frying remaining batches.

House Ranch

In a small bowl combine the mayonnaise, sour cream and buttermilk until smooth. Stir in chopped chives, parsley and dill. Season with garlic powder, onion powder, salt, pepper and lemon juice. Taste and adjust seasoning or thin with a bit more buttermilk if a looser consistency is desired. Chill at least 15 minutes to let flavors meld before serving.

Dirty Sauce (optional)

In a small bowl whisk together mayonnaise, ketchup, hot sauce, smoked paprika, Worcestershire sauce, pickle juice (if using) and black pepper. Taste and adjust heat or acidity as desired. Refrigerate until serving.