- Mix the flour, cornflour, paprika, and onion powder in a medium bowl until well combined. Dust each fish fillet with the flour mixture on all sides.
- Add 31⁄2 cm of vegetable oil to a heavy bottomed pot and heat to 180°C. Line 2 wire racks with 2 layers of paper towels each.
- Fry the potatoes in batches until a light tan colour and the edges are just starting to brown. Transfer the fried chips to one prepared racks to drain.
- When the potatoes are done frying, add the baking powder to the flour mixture and whisk together. Then add the cold beer to the flour mixture and lightly whisk together. Do not over mix the batter or it will end up heavy.
- Dip the fillets in the batter and fry them in batches. Flip the fillets over with tongs when you see the edges start to turn light brown. Transfer to the second prepared rack as they finish frying.
- Increase the heat of the oil to 200°C. Fry the chips a second time until they are golden brown and crisp. Drain on a rack and sprinkle with salt.
- Fry the fish a second time at the higher temperature until golden brown. Drain on a rack. Serve the fish and chips with lemon wedges and a tangy tartar sauce.