Prepare the Dry Ingredients: Whisk the four ingredients (flour, cornstarch, baking powder) plus salt, pepper and optional spices, if using, in a large bowl. These dry ingredients will make up the base of your batter
Add the Wet Ingredients: Still whisking, slowly pour the cold club soda or beer into the dry ingredients. The secret is to ensure your batter remains nice and smooth without any lumps. This will create a crispy coating after frying due to the cold liquid.
Add the Oil: Add 1 tbsp of vegetable oil into the batter mixture and Mix. This keeps the batter light and makes it manageable while frying.
Prepare the Seafood: Endeavour to dry your fillets with paper towels. This will assist in making the batter stick better. Set the fillets inside to be overly wet; it will cause a sliding batter whilst frying.
Heat the Oil: Heat the oil in a deep fryer or large heavy-bottomed pot to 350°F–375°F (175°C–190°C). Try to test with a thermometer, avoiding the smoke point where it is too hot. A soggy batter would have been because the oil was cold.
Batter the Seafood: Immerse the fresh fish in the prepared batter and make sure that they are thoroughly covered. Let the excess batter drop out.
Fry the Seafood: Now carefully slide the battered fillets into the hot oil, frying in batches to avoid overcrowding. Deep fry for 4 to 6 minutes till nicely golden brown and crispy. Turn the fillets halfway through to make sure all sides are being cooked.
Drain and Serve: Remove fillets from the oil and place them on a plate lined with a paper towel to absorb excess oil after frying. Pairs perfectly with a side of fries, coleslaw or some tartar sauce – best served immediately!