What is the main stuffing that defines lumpiang Shanghai?

The main stuffing that defines lumpiang Shanghai is ground pork.

Lumpiang Shanghai is a Filipino deep-fried roll made from giniling, or ground pork, mixed with finely chopped vegetables such as carrots, onions, scallions, and garlic. The mixture is rolled in a thin lumpia wrapper and fried until crisp. Although recipes can add many ingredients, ground pork is the characteristic main filling.

The name can mislead people into assuming that the dish originated in Shanghai or is simply a Chinese spring roll. In Filipino cuisine, however, lumpiang Shanghai is a localized dish and one of the most common foods served at parties and gatherings. It is usually smaller and thinner than several other lumpia types.

Ground beef, shrimp, chicken, peas, raisins, or other additions may appear in variations, but those do not change the canonical identity of the standard version. Mushrooms, tofu, and shredded beef are not the defining stuffing.