Prep all your ingredients. Clean your fish fillets and remove any bones.
Get a large freezer bag (or zip lock bag) and add 1 tsp of oil. Spread the oil evenly inside the bag and leave aside until needed.
Cut the fish into small cubes. Coat the fish with the potato starch in a mixing bowl.
Add the seasoning ingredients to the fish. Mix well.
Divide the the fish into 2 -3 equal portions (depending on the size of your food processor). Do the same with the dill and spring onions but keep them separate from the fish.
In a food processor, blitz each fish portion for roughly 30 seconds. Check the fish for consistency. If there are still chunks, continue to blitz until smooth.
Add one portion of the dill / spring onions mix and blitz for another 10 seconds.
Scoop the fish cake mixture out and place it into the freezer bag. Repeat until all the fish is done.
Push out as much air as you can from the freezer bag and then tie it up. Put the fish bag in another freezer bag.
Knead the fish cake mixture, for 5 minutes. Then drop the fish bag 10 times from a height to push out any air bubbles.
Put the fish cake mixture in the fridge for at least 30 minutes.
Once chilled, take the fish cakes out of the fridge. Put some oil on your hands and mold fish paste into 5 cm long x 2 cm thick round patties or into balls.
In a pot on medium heat, deep fry each patty for roughly 4 minutes on each side or until golden. If making fish balls, roughly 3 minutes in total.
Once done, take the fish cakes / balls out and check for doneness. If cooked, let them rest on a kitchen towels . If not, cook them until done.