Pat dry the fish thoroughly using a paper towel. Cut the fish into chunks approx. 1 inch (2.5 cm) thick. Pat dry again if necessary.
Prepare the breadcrumbs
In a large non-stick pan gently heat up the oil (do not let it burn). Add all the breadcrumbs and stir quickly to ensure they are evenly coated in the oil. Lower the heat and fry gently for about 6 minutes stirring all the time until golden. Transfer the breadcrumbs to a bowl and set aside to cool completely.
Assemble the recipe
Preheat the oven to 475F/ 240 C/ gas mark 9.Season the fish pieces on both sides.
Coat in the flour.
In a shallow bowl beat together the egg with the mustard and lemon zest until smooth (using a fork). Dip each fish chunk in the egg mixture gently wiping excess egg on the side of the bowl.
Coat in the crumb mixture lightly pressing in for even coverage (do this for each piece individually).
Lightly grease the rack so your cod nuggets do not stick to it. Arrange the pieces on top without touching one another and bake in the centre of the oven for about 12 minutes (this should be good for thicker pieces so bake 1-2 minutes less if your fish is not too thick).
Remove your baked fish nuggets from the oven and serve immediately.
Notes
Pat dry the fish thoroughly before seasoning.
Fry the breadcrumbs over a moderately low heat stirring all the time to ensure they do not burn. Cool completely before using.
Dip the fish bites in the egg mixture wiping excess egg on the side of the bowl (it shouldn’t be dripping).
Coat the fish chunks in the breadcrumbs as thoroughly as you can.
For a gluten free option use gf breadcrumbs and flour.
Lightly grease the rack before baking so your fish nuggets do not stick to it.
Bake in a preheated oven. There is no need to turn the fish over.