Pat the fish dry with a kitchen towel, cut into decent-sized pieces and sprinkle with salt.
Rinse the potatoes and cut into wedges. Place in a baking tray with melted butter and bake in a pre-heated oven at 180°C for around 45 minutes.
Tip: traditional fries may be substituted for roasted potato wedges. Do try these wedges though.
With the potatoes in the oven, prepare the mushy peas. Cook the peas for 2 minutes in salted water at a rolling boil, strain and leave a moment to steam before adding butter and roughly mashing. Finally, add chopped mint.
All of the ingredients for the mustard mayonnaise (egg yolks, sunflower oil, Dijon mustard, and lemon juice) should be at room temperature. Whip the oil into the egg yolks, adding the Dijon mustard and lemon juice to taste. Season the dip and place in the fridge to cool.
And so to the batter. Mix the sugar and plain flour. Now add the yolk from one egg (retaining the egg white) and the sparkling water. Whisk until smooth.
Beat the egg whites to a froth and carefully fold in to the batter.
Once the potatoes are nearly ready, heat the oil in a pan. Dip the fish in the batter and fry for 2 minutes each side. Remove from the heat and place on a kitchen towel to drain off excess fat.
There is no need to go overboard on presentation: chuck the fish and chips together on the plate with a wedge of lemon. The mushy peas and mustard mayonnaise may be served in dipping bowls. And now it’s time to get stuck in, eating with your hands and dunking for peas or mayo as you go!