Blitz the prawns and egg whites until smooth, use to fill 2 pieces of fish cover and chill overnight.

Heat a fryer to 190c or a deep pan of veg oil.

Whisk all the ingredients together for the batter coat the fish and deep fry until crisp and golden 3 to 4 minutes.

To make the mayo whisk the egg yolks and mustard and slowly drizzle in the oil until thick, ( you can do this in a small food processor)then mix in the vinegar herbs capers shallots, a squeeze of juice salt and pepper