4 large potatoes, peeled and cut into strips
1 cup all-purpose flour
1 teaspoon baking powder
1 teaspoon salt
1 teaspoon ground black pepper
1 cup milk
1 egg
1 quart vegetable oil for frying
1 ½ pounds cod fillets
Place sliced potatoes in a medium bowl and cover with cold water.
Mix flour, baking powder, salt, and pepper together in a separate medium bowl. Add milk and egg; stir until batter is smooth. Let stand for 20 minutes.
Meanwhile, heat oil in a large pot or electric skillet to 350 degrees F (175 degrees C).
Drain and pat dry potatoes. Fry in hot oil until tender, about 5 minutes; drain on paper towels.
Dredge cod in batter, one piece at a time, and place in hot oil. Fry fish in batches until golden brown on all sides; drain on paper towels. Monitor oil temperature, increasing the heat as needed to maintain 350 degrees F (175 degrees C).
Fry potatoes again in hot oil until crisp, 1 to 2 minutes; drain on paper towels.
