Prepare the potatoes: Begin by boiling the peeled potatoes in salted water until tender, about 10-12 minutes. Drain them well and mash them until smooth. Let the mashed potatoes cool for a few minutes before using them in the fish cakes.

Prepare the salmon mixture: In a large mixing bowl, combine the flaked cooked salmon, mashed potatoes, breadcrumbs, chopped herbs (parsley, dill, or both), Dijon mustard, lemon zest, lemon juice, chopped onion, and minced garlic. Add the beaten egg and stir everything together until well combined. Season with salt and freshly ground black pepper to taste.

Form the fish cakes: Once the mixture is fully combined, divide it into 8-10 equal portions (depending on the size you prefer for your cakes). Use your hands to shape each portion into a patty, about ½ to ¾ inch thick. Roll each patty in some extra breadcrumbs to coat lightly.

Cook the fish cakes: Heat the olive oil in a large skillet over medium heat. Once the oil is hot, add the fish cakes, cooking in batches if necessary to avoid overcrowding. Fry the fish cakes for 3-4 minutes on each side, or until they are golden brown and crispy on the outside and heated through in the center. Use a spatula to carefully flip the cakes.

Serve: Once cooked, transfer the fish cakes to a paper towel-lined plate to drain any excess oil. Serve the fish cakes hot, garnished with a wedge of lemon and your favorite dipping sauce, like tartar sauce or a simple yogurt-based sauce. A side of mixed greens or a light salad is a great accompaniment.