Sisig is the 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 locals who bought unused pig heads from the commissaries of nearby Clark Air Base in Angeles City, Pampanga. Pig heads were bought cheap since they are not used in preparing meals for the U.S. Air Force personnel stationed there. However, a more accurate explanation is just an innovation on the old recipe, which is pork ears and jowl, boiled, chopped then marinated.
The pig's head is first boiled to remove the hairs and to tenderize it. Afterwhich, it is chopped and grilled/broiled. It is then fried with onions and served on a sizzling plate.
Variations of sisig can 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, which brings sisig back to its origins.
An annual Sisig Festival (Sadsaran Qng Angeles) is held every year in the month of December in Angeles City, celebrating the said Kapampangan dish. It used to be held along the stretch of McArthur Highway in Balibago but is now celebrated at SM City Clark.