For the greatest degree of freshness, fish-lovers often buy their favorite fish whole -- salmon, snapper, catfish or flounder -- and fillet it at home. Look for fish with clear, well-rounded eyes; vividly colored gills; and a clean scent. Good fishmongers sell fish such as flounder already gutted, with the head on or off as you request. Filleting your own fish requires a small degree of effort, but the freshness makes it worthwhile.
Things You'll Need
- Cutting board
- Sharp, thin-bladed boning knife
Place the flounder on a clean cutting board with its dark side facing up. Feel for a hard bony ridge, called the gill plate, where the head joins the body. Make a semicircular cut with your knife tip, reaching underneath the gill plate to separate it from the fillets. Skip this if the fishmonger already removed the head.
Press your fingers lightly to the middle of the flounder, feeling for the dividing line where its muscles meet the backbone. Position the tip of your boning knife where that dividing line meets the gill plate, just behind the flounder's head. Cut through the skin and down to the bone, feeling for the bone with the tip of the knife. Draw the knife the length of the fish, following the line of the backbone, slicing through the skin and flesh.
Slide the tip of your knife back into that first cut and turn it to a horizontal position. Slide it along the flounder's bones until it reaches the skin at the outer edge of the fish, then draw your knife blade all the way back to the tail. The fillet should come away neatly, still connected to the flounder by the skin. Cut through the skin to release the first fillet.
Repeat that same process from the other side, to free your second fillet. Reverse the fillet and start at the tail end if you find it easier, rather than cutting in the "wrong" direction.
Turn the fish over, and locate the center line on its underside. Make an initial lengthwise cut, as you did with the top side of the flounder, then the same horizontal cuts to remove the two fillets.
Skin the fillets, if desired, by holding the tail end of the fillet in place on your cutting board and slicing down diagonally to the skin. Turn your knife blade until it's nearly horizontal, and slide it between the flounder's flesh and skin to separate them. Repeat for the remaining fillets.
Tips & Warnings
- This basic technique works for all flat bottom-dwelling fish, from tiny plaice to huge halibut. Some, such as plaice, have additional rows of bones that must be manually removed with tweezers or pliers.
- Most chefs use a flexible, thin-bladed boning knife for fish. The flexible blade bends flat against the rib bones, making it easier to remove the fillets. However, any sharp, thin-bladed knife will work.
- For the best results, cut away your fillets with long, smooth strokes rather than a short, sawing motion. Your first few fillets will likely be ragged, but you can easily camouflage that by breading them. After you've done a few, they'll be attractive enough to poach or bake.
- If you want to prepare the fillets with their skin on, scale the fish before you begin cutting it.
- If you caught your own flounder, or bought a fish whole from a fisherman or fishmonger, the guts might be intact. Because of their odd anatomy, this doesn't change how you fillet and debone the fish. The guts are contained entirely within the rib cage, so if you're careful not to cut through any bones, the guts will be left behind in the skeleton.
- Flounder and other fresh fish are highly perishable and should always be kept on ice or refrigerated until you cook them.
- On Cooking: A Textbook of Culinary Fundamentals; Sarah Labensky, et al.
- Photo Credit John Foxx/Stockbyte/Getty Images