Divide the mackerel carcasses into four identical parts (each fish into two halves). Put the skin down in a bowl and pour the marinade (spread the vegetables on top of the fillet).
Marinade: finely chop a white onion and a tomato, add two tablespoons of oil, a teaspoon of soy sauce, a large clove of garlic, paprika, black pepper, a drop of lemon juice (very carefully), salt to taste and more fresh or frozen dill (with a portion of tomato). – mix everything up.
Put the bowl in a bag and refrigerate for an hour.