In a large bowl, mix the flour, baking powder, salt, and beer (or sparkling water) until smooth. The batter should be thick enough to coat the back of a spoon. Set aside.

Heat the Oil

In a deep skillet or fryer, heat the vegetable oil over medium-high heat until it reaches 350°F (175°C).

Coat and Fry the Fish

Dip each fish fillet into the batter, allowing excess to drip off. Carefully place the battered fish into the hot oil and fry for about 4-5 minutes on each side, or until golden brown and cooked through. Remove and drain on paper towels.

For the Fries

Prepare the Potatoes

Peel the potatoes and cut them into thick strips. Rinse them under cold water to remove excess starch.

Heat the Oil

In a separate deep skillet or fryer, heat the vegetable oil over medium-high heat until it reaches 350°F (175°C).

Fry the Potatoes

Carefully add the potato strips to the hot oil in batches. Fry for about 5-7 minutes, or until they are golden brown and crispy. Remove and drain on paper towels. Sprinkle with salt to taste.

For the Tartar Sauce

Mix the Ingredients

In a small bowl, combine the mayonnaise, dill pickles, capers, lemon juice, salt, and black pepper. Mix well until all ingredients are evenly incorporated. Refrigerate until ready to serve.