Fish add salt and sprinkle with pepper. Once mature for 10-15 minutes, add some flour and fry in very preheated oil until golden color. Remove to a warm plate. In the fat from frying sauté chopped onions and mushrooms, sprinkled with a little salt and pepper. Distributed in dishes for serving, put them on fish, pour in the melted butter, garnished with lemon slices and sprinkle with parsley.