1
Make 4-5 deep cuts into the flesh on each side to allow the deep-frying oil to penetrate it: lay the fish on its side and cut down into the thickest part of the fish near the backbone, about 2-inch (5cm) from the base of the fish head and at right angles to the backbone itself. When the knife touches the bones of the spine, swivel the blade inside the flesh to face the head and continue cutting parallel to the backbone and towards the head for about another 1.25-inch (3cm). This will create a thick flap of fish flesh. Make further, similar cuts at 2-inch (5cm) intervals until you reach the thinner tail flesh, and then repeat on the other side of the fish, again cutting down to the spine and back towards the head. (When you have finished, if you hold the fish upside down by its tail, the flaps should all hang outwards slightly.)