Place the potato strips in a bowl of cold water and let them soak for at least 30 minutes to remove excess starch.
Drain the potatoes and pat them dry with paper towels.
Heat vegetable oil in a deep fryer or large pot to 325°F (165°C).
Fry the potatoes in batches for about 4-5 minutes until they are tender but not browned.
Remove the potatoes from the oil and let them drain on paper towels.
In a large bowl, whisk together 1 cup of flour, baking powder, and a pinch of salt.
Gradually add the cold beer or sparkling water, whisking until the batter is smooth and has the consistency of heavy cream.
Season the fish fillets with salt and black pepper, then dredge them in flour, shaking off any excess.
Increase the oil temperature to 375°F (190°C).
Dip each floured fish fillet into the batter, allowing any excess to drip off.
Carefully place the battered fish into the hot oil and fry for about 4-6 minutes, or until the batter is golden brown and the fish is cooked through.
Remove the fish from the oil and drain on paper towels.
Increase the oil temperature back to 375°F (190°C) if it has cooled down.
Fry the pre-cooked chips in batches for another 2-3 minutes, or until they are golden brown and crispy.
Remove the chips from the oil and drain on paper towels.
Season with salt to taste.
Enjoy your meal!