Combine all ingredients and mix well. Depending on how sticky the mixture is, use up to the full half-cup of potato starch. On a cookie sheet lined with parchment paper and dusted with potato starch, drop spoonfuls of fish mixture with a spoon or ice cream scoop and flatten to form thick patties, then dust tops with potato starch. Place cookie sheet in freezer for 20 minutes to one hour to harden fish cakes and make them easier to handle.

In a frying pan, heat a few tablespoons of oil over medium heat. Fry fish cakes for two to three minutes per side or until golden. The cakes can be served at room temp or slightly heated in a warm (not hot) oven, being careful not to dry them out.

Make carrot ribbons by peeling carrots into a bowl until barely any carrot is left. In a salad bowl, combine minced ginger, lemon zest and juice, sugar, salt and pepper and olive oil and whisk to combine. Add carrot ribbons and chopped parsley and mix.

Mound carrot salad on a plate or serving platter, then place fish cakes on top. Lightly drizzle tops of fish cakes with white horseradish sauce.