1 large Spanish onion, sliced into 1-cm (1/2-inch) rounds and separated into rings (if desired, set aside the small centre rings for another use)
1/4 cup cornstarch
1 cup pastry flour
2 tbsp cornstarch
1/4 tsp baking powder
1/4 tsp salt
1 cup pale ale
Oil for frying
Preheat the deep fryer to 190°C (375°F). Place a cooling rack on a baking sheet or line a baking sheet with paper towels.
In a paper bag or large bowl, toss the onion rings in the cornstarch to coat well. Set aside.
In a bowl, combine the flour, cornstarch, baking powder and salt. Whisk in the beer.
Using your fingertips or a wooden chopstick, dip the rings in the batter, 4 or 5 at a time.
Shake off excess batter and deep-fry for about 3 minutes, turning half way through cooking.
Drain on the baking sheet.
Season lightly with salt.
Repeat with the remaining ingredients.