750 g (1 1/2 lb) floury potatoes, peeled and cut into 1-cm (1/2-inch) thick chips
200 ml (7 fl oz) vegetable stock
4 cod fillets, about 175 g (6 oz) each, skin on
2 tablespoons cornflour
salt and pepper
lemon wedges, to serve
Heat the butter in a small saucepan and cook the spring onions for 2 minutes until softened. Add the peas and stock and simmer for 3 minutes. Roughly mash and keep warm.
Meanwhile beat together the flour and beer, then season well with salt and pepper.
Fill a large, deep saucepan one-third full with oil and heat until a cube of bread browns in 30 seconds. Pat the chips dry with kitchen paper. Deep-fry in batches for 5 minutes until golden.
Season the fish and dust with the cornflour. Dip into the batter until coated, shake off any excess and deep-fry in batches for 7 minutes, using tongs to turn the fish over. Drain on kitchen paper. Keep warm in a low oven. Increase the heat until a cube of bread browns in 15 seconds. Deep-fry the chips again in batches for 2 minutes until crisp and golden. Serve with the fish and mushy peas with lemon wedges on the side.