A fillet is a boneless cut of meat; you may also see this term spelled “filet,” especially in British English. Many people associate this cut specifically with fish, which are often filleted for the market, but fillets can technically be cut from any food animal, from a chicken to a cow. The flavor, texture, and tenderness of fillets varies widely, depending on what part of the animal the cut is taken from, and how it is prepared. Most markets and butchers carry an assortment of fillets for their customers, and it is also possible to fillet meat at home, with the assistance of a well sharpened fillet knife.
In the case of fish, the fillet is often the preferred cut for consumers because fish bones are difficult to deal with. These small bones can be very hard to remove, and they pose a risk to diners because they can catch in the mouth or throat, causing choking. By cooking with fillets, cooks can be assured that the risk of fish bones in the dish is greatly reduced, although diners should still be careful, because bones can slip through during the filleting process.
Fillets cut from animals like chickens and cattle come in a variety of shapes and sizes, and they are often chosen from very tender parts of the body, as is the case with fillet mignon, a popular cut of beef. Fillets from these animals also tend to be very thin, maximizing the amount of meat which can be removed from the animal, and as a result they cook very quickly.
Because fillets lack bones, they tend to be less flavorful than cuts which include bones, and they are also prone to drying out if they are cooked to long. The flip side of the fillet cut is that it is easy to prepare, and it cooks more quickly than bone-in cuts, because it lacks the density of bone-in cuts. A fillet can also be rolled up to make dishes like chicken Kiev, or wrapped around other cuts of meat and vegetables before being roasted, grilled, or fried.
There are all sorts of ways to use a fillet of meat. When cooking with fillets, it is important to remember that the cooking time is usually quite brief, and that fillets benefit greatly from being marinated, basted, or glazed to keep the meat moist and seal in some of the natural flavors of the meat.