How to fillet a flat fish
The short answer
Cut around the head, then down the centre line of the fish to the backbone, and work the blade outward over the rib bones to the fin edge to lift a quarter fillet. A flat fish gives four quarter fillets, one from each side of the backbone top and bottom, or two larger fillets if you take each whole side in one piece.
Step by step
1. Lay the fish dark-side up on a board with the tail towards you. Use a sharp flexible filleting knife. 2. Make a cut around the head and gill line, following the natural curve. 3. Cut straight down the centre line from head to tail, feeling for the backbone, until the knife rests on the bone. 4. Turn the blade almost flat and sweep it outward over the rib bones towards the fin edge, using long strokes, until the quarter fillet lifts away. 5. Repeat on the other side of the centre line to release the second quarter. 6. Turn the fish over and take the two fillets from the underside the same way. 7. For two fillets instead of four, work each whole side off in one piece rather than stopping at the centre line. 8. Skin the fillets if you wish. On Dover sole the skin peels off whole once you nick the tail.
Which fish it suits
This is the method for flat fish, the ones with both eyes on one side: plaice, lemon sole, Dover sole, dab, brill, turbot, megrim and flounder. Smaller flat fish give four neat quarter fillets. Larger ones like turbot, brill and halibut are usually taken as two broad fillets a side because there is more flesh to lift.
Round fish such as sea bass and mackerel are filleted the other way, along the spine from head to tail.
Tips / common mistakes
- Keep the blade almost flat and let it ride over the rib bones so you leave little flesh behind.
- Feel the frame through the knife. The bones tell you where to go.
- Long sweeping strokes give clean fillets, while short sawing tears them.
- Dover sole is the exception for skinning. Score across the tail, lift a flap of skin and pull it off whole.
- If you would rather skip the knife work, the counter fillets and skins every flat fish free by hand, cut to order.
Frequently asked questions
How many fillets does a flat fish give? Four quarter fillets from a smaller fish, two from each side of the backbone, or two broad fillets a side on a larger flat fish like turbot or brill.
What is the difference between quarter fillets and cross-cut fillets? Quarter fillets are lifted from each side of the centre line and are neat single strips. Taking a whole side in one piece gives you one larger fillet per side instead.
How do you skin a Dover sole? Score across the tail, work a thumb under the edge of the skin and pull it off in one piece towards the head. It comes away cleanly, unlike most fish where you skin with a knife.
What knife do you need to fillet flat fish? A thin flexible filleting knife around 15 to 18cm, so the blade can follow the flat frame and stay against the bones.
Can you fillet it for me? Yes. We fillet, trim and skin flat fish free by hand at the counter, cut to order, whether you want four quarter fillets or two.
