Peel and quarter the potatoes and place in a medium sauce pan covered in water. Boil the potatoes for 15 minutes, then mash. Set aside.
Place the cod and the sliced onions into a large pot and cover with water. Simmer the cod over medium high heat for 5 minutes until it's cooked. Drain the fish and flake with a fork, combining the onions with the fish
In a large bowl or the stock pot, mix together the cod, onion, mashed potatoes, panko, parsley, dill, garlic, capers, eggs, lemon zest and juice, salt and pepper. If you'd like to use parmesan cheese, you can add it at this time as well. It adds a salty and creamy texture to the fishcakes. it is not traditional, but it adds great flavor.
Scoop 1/3 cup of the mixture and form into patties. You'll get 8 fishcakes with this recipe.
Place on a parchment lined baking sheet and refrigerate for 15 minutes, or up to an hour.
When ready to cook, choose one of the three methods below.
We tested pan-frying in shallow oil and butter, air frying and broiling. I prefer the pan-fried fishcakes because the oil and butter helps them stay moist, whereas the air fried and broiler methods use much less oil, so the fishcakes were a little more dry. But the fishcakes taste great, no matter which method you choose. if you are cooking all 8 fishcakes at once, you may prefer the broiler method.