Combine the ground meats, salt, pepper, parsley (except for the parsley garnish), and the scallions. Mix well with your hands, then set aside.
Place the slices of meat between two sheets of waxed paper. Pound with a mallet or an empty wine bottle so that the slices thin out and expand. Any very large slices may be halved. Spread each slice with the ground meat mixture, making a ¼-inch l