Slices of fish is lightly crushed with a wooden mallet and marinated with lemon juice, salt and pepper. After 30 minutes, drain, rolled in flour and fry in fat than many heated vegetable oil. Remove to a plate, and the fat fry the onion, cut into rings and fried in flour until browned. Steaks are covered with melted butter and covered with roasted onions. Garnish with slices of red tomatoes, dusted with a pinch of salt and chopped parsley.