cornstarch, divided
kosher salt, divided, plus more for sprinkling
ground black pepper, divided
all-purpose flour
baking powder
paprika
bottle lager, cold
Vegetable oil, for frying
1-inch thick skinless cod filets
Lemon wedges, for serving
Malt vinegar, for serving
mayonnaise
dill pickle relish
lemon zest
lemon juice
chopped fresh dill
kosher salt
ground black pepper