Mix Dry Ingredients: In a large mixing bowl, whisk together the all-purpose flour, cornstarch, baking powder, salt, garlic powder, and paprika. The cornstarch and baking powder are key to getting that crispy texture.
Add Wet Ingredients: Gradually add the cold water and cold club soda to the dry ingredients while whisking to form a smooth batter. The cold ingredients help create a light and crispy coating. If you prefer a thicker batter, you can add a bit more flour. For extra richness and crispiness, you can add an egg, but it’s optional.
Check the Consistency: The batter should be thick enough to coat the back of a spoon but still pourable. If it's too thick, add a little more cold water or club soda. If it’s too thin, add a little more flour.
Heat the Oil: Heat your oil in a deep fryer or large skillet to 350°F (175°C). You’ll need enough oil to submerge the food you plan to fry.
Coat Your Food: Dip your fish fillets, shrimp, or other seafood into the batter, ensuring each piece is fully coated.
Fry to Golden Perfection: Carefully lower the battered seafood into the hot oil. Fry in batches to avoid overcrowding, and cook until the coating is golden brown and crispy, typically 3-5 minutes, depending on the size of the pieces. Use a slotted spoon or tongs to remove the food and place it on a paper towel-lined plate to drain excess oil.