Step 1: Prep the Fish

1. Pat the cod fillets dry with paper towels.
2. Place them in a shallow dish with buttermilk and let soak for 15-20 minutes. This helps keep the fish tender and adds flavor.

Step 2: Prepare the Breading Station

1. In a shallow dish, whisk together flour, cornmeal, salt, pepper, garlic powder, onion powder, paprika, and cayenne pepper.
2. In another bowl, beat the egg.
3. In a third dish, add panko breadcrumbs.

Step 3: Bread the Fish

1. Remove each cod fillet from the buttermilk, letting excess drip off.
2. Dredge in the flour mixture, coating well.
3. Dip into the beaten egg, then press into the panko breadcrumbs, ensuring an even coating.

Step 4: Fry the Fish

1. Heat about 2 inches of oil in a deep skillet or fryer to 350°F (175°C).
2. Fry each fillet for 3-4 minutes per side, or until golden brown and crispy. The internal temperature should reach 145°F (63°C).
3. Transfer to a paper towel-lined plate to drain excess oil.

Step 5: Assemble the Sandwich

1. Toast the buns in a dry skillet or under the broiler for extra flavor.
2. Spread tartar sauce on the bottom bun.
3. Layer with lettuce, tomato slices, and pickles.
4. Place the crispy cod fillet on top and add a slice of cheese (if using).
5. Top with the other half of the bun and enjoy!