Peel potatoes and coarsely grate them. Squeeze out all excess moisture.

Coarsely grate the onion and divide it into two portions. Reserve half for the sauce.

Chop the white and smoked fish fillets roughly.

Place the chopped fish in a food processor with some freshly ground black pepper and blend to a smooth paste.

Combine the fish paste with the grated potatoes and half of the grated onion. Add salt as desired.

Shape the mixture into 8 round cakes and set aside.

Wash the food processor and add herbs and blend until finely chopped.

Add the remaining sauce ingredients (including the reserved grated onion) and pulse to a slightly chunky puree.

Taste the sauce and adjust salt and pepper as desired. Transfer to a bowl and set aside.

Lightly dust the fish cakes with flour.

Heat canola oil to a depth of 1/2-inch in a pan.

Fry the cakes in two batches for about 3 minutes on each side over medium heat.

Drain the fish cakes on paper towels and reheat the oil to cook the second batch.

Serve the fish cakes with the herbed sauce and a fresh tomato salad.