Add the potatoes to a bowl of cold water to remove excess starch and prevent discoloration.
2. Step
Pour oil to a depth of 6 inches (15 cm) in a large heavy pot. Heat over medium-high heat until oil reaches 325˚F (160˚C).
3. Step
Drain the potatoes and blot dry thoroughly with paper towels.
4. Step
Working in batches, fry the potatoes in the hot oil for about 5 minutes, or until pale golden. With a slotted spoon or spider, transfer to a wire rack to drain. Season with salt.
5. Step
Increase the heat to high. When the oil temperature reaches 375˚F (190˚C),return the fries to the pot and fry until golden brown. Transfer to the rack to drain again and season with more salt.
6. Step
Reduce the heat to medium-high to let the oil temperature reduce to 350˚F (180˚C).
7. Step
Pat the cod fillets dry with a paper towel. Season all over with salt and pepper.
8. Step
Add 1 cup (125 G) of flour to a plate. Dredge the cod in the flour, shaking off any excess.
9. Step
In a large bowl, whisk to combine the remaining 1½ cups (185 G) of flour, 1 teaspoon salt, and baking powder. Gradually add the beer, whisking until smooth.
10. Step
Dip the dredged cod in the batter, turning to coat completely.
11. Step
Fry the cod in the hot oil until golden brown on all sides, 3-5 minutes. Transfer to a wire rack to drain for 3 minutes. Season with salt.
12. Step
Garnish the fish and chips with parsley and serve with lemon wedges, tartar sauce, ketchup, and malt vinegar.
