½ cup all purpose flour
¼ cup cornstarch
big pinch cayenne pepper
several shakes black pepper
1 cup cold club soda
2-3 cups Panko bread crumbs (this is important!)
2 large sweet onions
2-3 cups vegetable oil for frying
Whisk together flour, cornstarch, spices, club soda until smooth. Refrigerate 10 minutes.
Meanwhile spread Panko in a shallow bowl and cut onions into thick ¾" rings.
Heat oil to 350ºF
Stir batter once more, thinning with additional water if necessary (should be a little thicker than pancake batter) and use a fork to dip onion rings into batter.
Let excess drip off, then coat in Panko.
Fry onion rings 2-3 minutes until golden.
Drain on paper, sprinkle with salt, serve hot.