Шаг 1
Wash, clean, and cut the fish into small pieces.
Шаг 2
Make the breading: in a flat dish, mix flour, salt, and pepper. Dredge the fish pieces in the mixture and place them on a rimmed baking tray.
Шаг 3
Slice the onion into half-rings and sauté in vegetable oil.
Make the sauce: mix sour cream with mustard, eggs, finely chopped dill (optional: add salt), and the sautéed onions. Stir well.
Шаг 4
Pour the prepared sauce over the fish.
Шаг 5
Grate cheese on top and place in a preheated oven (200°C).
Шаг 6
Bake until golden crust forms.