Preheat your oven to 425°F (220°C). Wash and peel the russet potatoes. Cut them into even-sized fries.

In a large bowl, toss the potato fries with olive oil, smoked sea salt, and black pepper until evenly coated. Spread the fries in a single layer on a baking sheet lined with parchment paper. Bake for 30-35 minutes, flipping halfway through, until golden and crispy.

In a medium bowl, combine the mayonnaise, Dijon mustard, chopped capers, chopped dill pickles, lemon juice, salt, and pepper. Mix until well combined. Taste and adjust seasoning if necessary. Refrigerate until ready to serve.

In a large bowl, whisk together the flour, cornstarch, baking powder, smoked sea salt, and black pepper. Gradually add the cold beer (or sparkling water), stirring until the batter is smooth and has no lumps.

Heat vegetable oil in a deep frying pan over medium-high heat until hot (about 350°F or 175°C). Dip each fish fillet into the batter, allowing any excess to drip off. Carefully place the battered fillets into the hot oil, frying in batches to avoid overcrowding.

Fry for about 4-5 minutes on each side or until golden brown and crispy. Remove and place on a paper towel-lined plate to drain excess oil.

Serve the crispy batter-fried fish fillets hot, alongside the chunky tartar sauce and golden sea salt fries. Enjoy your meal!