In a nonstick skillet, put about an inch of water in the bottom and bring to a simmer over medium high heat. Season fish with ¼ teaspoon of the salt and add to the pan. Cover pan and simmer over low heat until just done, 6 to 8 minutes. Remove from pan with slotted spoon and drain on paper towels. Pour out water and dry the pan. Allow fish to cool slightly, about 5 minutes and pat completely dry.
Flake fish in medium bowl with forks removing any bones as you go. Add yogurt, parsley, egg yolk, mustard, lemon juice, 6 tablespoons of the bread crumbs, scallions, pepper and remaining ¼ teaspoon salt and stir to combine. Shape mixture into 8 round cakes. Coat cake with remaining half of bread crumbs.
Heat 2 tablespoons of the oil in the nonstick skillet over medium heat. Add cakes and cook until brown and crisp, 2 to 3 minutes. Add the remaining 2 tablespoon of oil, turn cakes and cook until golden brown on the other side, 2 or 3 minutes longer. Drain on paper towels.
Serve with tartar sauce or your favorite dipping sauces.