01 -
Pour vegetable oil into a deep fryer or large saucepan and heat to 350°F (175°C).
02 -
In a medium mixing bowl, whisk together the flour, cornstarch, baking powder, kosher salt, and cayenne pepper. Gradually add cold water, whisking until a smooth, slightly foamy batter forms.
03 -
Gently pat the fish fillets dry with paper towels to remove excess surface moisture. Dip each fillet into the batter, ensuring an even coating.
04 -
Carefully place the coated fillets into the hot oil. Fry for 3 to 4 minutes, or until each fillet is golden brown and the coating is crisp. Avoid overcrowding the fryer by working in batches.
05 -
Transfer the fried fillets to a wire rack to drain excess oil before serving.