Mix flour, baking powder, and salt in a bowl
Add egg and beer and whisk together into a smooth batter
Crush cornflakes and pour them into a deep plate
Cut the haddock fillets into pieces 3-4 cm wide
Pour oil into a saucepan and turn on medium-high heat (or use your deep fryer if you have one!)
Dip the haddock pieces in batter, coat them in cornflakes, and fry a few pieces at a time until they are golden brown (I aim for cognac brown, maybe a bit darker)
Then place the haddock pieces on a piece of paper to absorb the excess oil, and sprinkle with salt and pepper
Serve with remoulade or tartar sauce and fries or oven potatoes