Sisig is a Kapampangan term which means "to snack on something sour". It usually refers to fruits, often unripe or half-ripe, sometimes dipped in salt and vinegar. It also refers to a method of preparing fish and meat, especially pork, which is marinated in a sour liquid such as lemon juice or vinegar, then seasoned with salt, pepper and other spices.
The dish is said to have originated from local residents who bought unused pig heads from the commissaries of Clark Air Base in Angeles City, Pampanga. Pig heads were purchased cheap since they were not used in preparing meals for the U.S. Air Force personnel stationed there. An alternate explanation of its origin is that it is but an innovative variation on an older recipe, which is pork ears and jowl, boiled, chopped then marinated.
Preparing sisig comes in three phases: boiling, broiling and finally frying. A pig's head is first boiled to remove hairs and to tenderize it. Portions of it are then chopped and grilled or broiled. Finally, it is fried with onions and served on a sizzling plate. Variations of sisig may add any of the following: eggs, ox brains, chicharon (pork cracklings), pork or chicken liver, and even mayonnaise. Recently, local chefs have experimented with ingredients other than pork such as chicken, squid, tuna and even tofu.