Begin with the dredging mix by combining ½ cup of cornstarch, 2 teaspoons of kosher salt, and 1 teaspoon of ground black pepper in a shallow dish. Set this aside for coating the fish before battering.

In a large mixing bowl, whisk together the flour, baking powder, paprika, the remaining 1 cup of cornstarch, 2 teaspoons salt, and 1 teaspoon pepper. Slowly pour in the cold beer and mix gently just until a smooth batter forms. Avoid overmixing to keep the texture light. Cover the bowl and refrigerate the batter until you're ready to fry.

For the tartar sauce, mix the mayonnaise, dill pickle relish, lemon zest, lemon juice, fresh dill, salt, and pepper in a medium bowl until well combined. Cover and chill until serving time to let the flavors meld.

Heat about 2 inches of vegetable oil in a deep Dutch oven or heavy-bottomed pot to 375°F. Line a baking sheet with paper towels or place a wire rack over it to drain the cooked fish.

Pat the cod fillets dry with paper towels and slice into 10 to 12 pieces, about 3 inches each. Lightly dredge the fish in the cornstarch mixture, shaking off any excess.

Working in small batches of 3 to 4 pieces, dip the fish into the chilled beer batter, allowing any excess to drip off. Carefully lower the battered fish into the hot oil and fry for 2 to 3 minutes, flipping as needed, until golden and crispy. Transfer the cooked fish to the wire rack and immediately season with a pinch of salt.

Repeat the frying process until all the fish is cooked. Serve hot alongside homemade tartar sauce, lemon wedges for squeezing, and a dash of malt vinegar for that classic tangy finish.