Cut fish fillets into two inches by one and a half inch sized pieces. Grind together coconut, coriander leaves, salt, green chillies, cumin seeds, garlic and lemon juice to a smooth chutney.
Marinate the fish pieces in this chutney for about fifteen minutes. Cut banana leaves into smaller pieces. Place the marinated fish in the center of each banana leaf piece and smear some of the chutney on them.
Fold in the ends to make a parcel. You can either steam these fish parcels or cook on a tawa. To steam just place them in a steamer and steam for five minutes. To cook on a tawa, heat oil and place the parcels on it.
Cook turning the parcels from time to time so that they get cooked on both the sides. When the banana leaves turn light brown take them off the tawa. Do not open the parcels while serving. Let the person eating them open.