1. Prepare the Tartar Sauce (Optional)

If making homemade tartar sauce, combine the mayonnaise, pickle relish, Dijon mustard, lemon juice, garlic powder, salt, and pepper in a small bowl. Mix well and refrigerate until ready to use.

2. Prepare the Batter

In a medium bowl, whisk together the flour, cornstarch, garlic powder, onion powder, smoked paprika, cayenne pepper (if using), salt, and black pepper. Gradually whisk in the cold club soda until the batter is smooth and has the consistency of pancake batter. Be careful not to overmix; a few small lumps are okay.

3. Preheat the Oil

Heat the vegetable oil in a large skillet or heavy-bottomed pan over medium-high heat until it reaches 350°F (175°C). If you don’t have a thermometer, drop a small amount of batter into the oil—it should sizzle and float immediately.

4. Coat and Fry the Cod

Pat the cod fillets dry with paper towels to remove any excess moisture (this helps the batter stick better). Dip each fillet into the batter, ensuring it’s fully coated, then carefully lower it into the hot oil. Fry the cod in batches for 3-4 minutes per side, or until the coating is golden brown and crispy and the fish is cooked through (internal temperature of 145°F/63°C).

Use a slotted spoon or tongs to remove the fillets from the oil and place them on a plate lined with paper towels to drain any excess grease.

5. Toast the Buns

While the cod is frying, lightly toast the sandwich buns in a skillet or toaster for added flavor and texture.

6. Assemble the Sandwiches

Spread tartar sauce on the bottom half of each bun. Layer with shredded lettuce, a slice of tomato, and any optional toppings you like (e.g., pickles, coleslaw, or cheese). Place the fried cod fillet on top and finish with the top half of the bun.

7. Serve and Enjoy

Serve the sandwiches immediately with lemon wedges on the side for an extra burst of brightness. Pair with fries, coleslaw, or a simple salad for a complete meal.