Remove scales from steak. To keep your kitchen clean, use a plastic bag to clean the scales. Place the fish in it and remove the scales with a small knife. Rinse and pat dry the fish with a paper towel. Preheat the oven to 200°C and prepare the foil.
Rub the steak with a mixture of salt and pepper, generously sprinkle with lemon juice and brush with olive oil. Leave the fish in this marinade for a short time.
Place the prepared steak on foil, add rosemary and wrap in a tight envelope. Bake the steak in an oven preheated to 200°C for 20 minutes.
10 minutes before cooking, open the envelope with fish using tongs. Place thin slices of lemon on the surface and return to the oven to brown the fish.