Rinse and slice the potatoes into thin fries. Place the cut potatoes into a bowl and cover with cool water. Rinse the fries until the water is clear.
Drain and place the fries on a towel and pat dry. Set aside.
Slice the fillets in half and then into bite-sized pieces to ensure an even frying time. Place the pieces on a paper towel and pat dry. If you’re not frying the fish right away, place the filets in the fridge until ready to fry.
In a large bowl, combine the flour, cornstarch, baking powder and Original seasoning. Whisk in 12 ounces of beer, until smooth. Add a little more beer if needed to achieve a pancake batter consistency.
In a Dutch oven or deep fryer, add about 3 to 4 inches of the fry oil and heat to 350 degrees F.
Dust the filets lightly with cornstarch to help the batter stick to the fish. Dip the filets in the wet mixture and then place in the oil, a few at a time. Fry for about 3 to 4 minutes, turning as needed, or until golden brown. Place on a wire rack in a warm oven to stay warm.
Mix in 2 to 4 ounces of the remaining beer into the batter mixture until it reaches a thin pancake batter consistency. Dip the potatoes in to thoroughly coat. Add the fries, a few at a time, to the oil and fry for 3 to 4 minutes, or until golden brown. Place on a wire rack to drain.
Serve fish and chips warm with tartar sauce and/or ketchup.