Rinse potato sticks under cold water until runoff runs clear, then soak in a large bowl of ice water for 20–30 minutes (this is the secret to extra-crisp fries!).

In a heavy Dutch oven or deep fryer, heat oil to 350°F (175°C). Use a candy or frying thermometer—this little tool is a game-changer.

Pat your fish pieces completely dry, then season with salt and pepper. Dredge lightly in flour, shaking off any excess.

In a bowl, combine 1 cup flour, baking powder, and a pinch of salt. Whisk in the beaten egg and cold beer until smooth. Let it rest for 5 minutes so bubbles form—this keeps the batter airy.

Drain potatoes, pat dry, then toss with corn starch (if using). Fry in batches for 3–4 minutes—fries should be pale and slightly tender, not golden. Remove and drain on paper towels.

Dip each floured fillet into the beer batter, letting excess drip off, then gently lower into hot oil. Fry for about 5–6 minutes, turning halfway, until golden brown and the fish reaches 145°F internally. Drain on a wire rack over a baking sheet.

Increase oil temperature to 375°F (190°C). Fry the par-fried potatoes in batches for 2–3 minutes until golden and extra crispy. Drain and immediately season with salt.

Arrange fish and chips on a platter lined with parchment or newspaper (for nostalgia!). Garnish with lemon wedges and serve alongside tartar sauce and vinegar for dipping.