For the fish
50g plain flour
1 tsp baking powder
75ml lager beer
75ml sparkling water
about 1 litre sunflower oil, for frying
400g fillet sustainable cod, hake or haddock, halved
For the chips
750g potatoes, peeled and sliced into thick chips
2 tbsp plain flour
2 tbsp sunflower oil
Combine the flour, cornflour, baking powder and turmeric in a large bowl, season, then spoon 1 tbsp onto a plate and set aside. Gradually pour the beer and water into the bowl, stirring with a wooden spoon until you have a smooth, lump-free batter. Leave to rest for 30 mins while you prepare the chips.
Heat oven to 200C/fan 180C/gas 6. Boil a large pan of water, then add the chipped potatoes and boil for 2-3 mins until the outsides are just tender but not soft. drain well, then tip onto a large baking tray with the flour, oil and some salt. Gently toss together until all the potatoes are evenly coated and the flour is no longer dusty. Roast for 30 mins, turning occasionally, until the chips are golden and crisp.
To cook the fish, heat the 1 litre oil in a deep saucepan until a drop of batter sizzles and crisps up straight away. Pat the fish dry with kitchen paper, then toss it in the reserved turmeric flour mix. Shake off any excess, then dip into the batter. Carefully lower each fillet into the hot oil and fry for 6-8 mins – depending on the thickness of the fish – until golden and crisp. Using a large slotted spoon, lift out the fish, drain on kitchen paper, then sprinkle with salt.