1.Salt the cod portions for 1 hour then rinse and wrap in Clingfilm.
2.Blitz the breadcrumbs, herbs and cheese & then roll out and freeze for 1 hour then slice into small thin portions for thefish.
3.Simmer the diced potatoes in salted water for about 7 minutes until barely tender. Drain, refresh in cold water and set aside.
4.To make the sauce: put the egg yolk, mustard and wine vinegar into a bowl and whisk for 1 minute to combine. Slowly add the olive oil, drop by drop to begin with, then in a steady stream, whisking constantly, until the mixture is emulsified and thick. Season the mayonnaise with a little salt. 4. When ready to serve the fish, finish the sauce. Add the cream to the mayonnaise, then slowly whisk in the hot fish stock, until the sauce is thick enough to just coat the back of the spoon. Add the lettuce and peas to the sauce and heat through for 1 minute. Finally add the diced gherkins and chopped herbs. Season with salt and pepper to taste. Put to one side.
5.Heat the oil for deep frying in a deep fryer or other suitable deep, heavy pan to 180°c. Deep fry the potato cubes for 4 minutes until crispy and golden. Drain on kitchen paper and keep warm.
6.Heat a frying pan and add a drizzle of oil. When hot, add the cod portions and season with a little salt. Cook gently for 2 minutes until the fish is lightly golden at the edges. Carefully flip the fish over & place the crust on and finish under the grill.
7.Deep fry the capers until they flower & crisp up & then mix the lemon juice and olive oil & plate up.