- 3 tablespoons oil
- 6 cups shredded napa cabbage (about 1/2 a medium head)
- 6 ounces pork shoulder, trimmed of gristle, cut into 1/4 inch by 2 inch slices
- 2 teaspoons cornstarch mixed with 3 tablespoons water
- 1 quart oil for deep-frying
Heat 3 tablespoons oil in a wok over high heat until smoking. Add half of cabbage, season with salt, and cook, stirring and tossing occasionally, until softened and wilted, about 2 minutes. Add remaining cabbage and cook, stirring occasionally, until wilted. Add water to cover, bring to a boil, reduce to a bare simmer, cover, and cook for 1 hour, adding more water as necessary. Add sliced pork and stir around to distribute. Continue to simmer for 1 more hour, adding water as necessary, until the cabbage is extremely tender and liquid is completely reduced.
Add cornstarch slurry and let the mixture come to a simmer, cooking until the mixture is thickened, about 3 minutes. Transfer to a large bowl.
Wrap spring rolls using this technique, using about 3 tablespoons of filling per roll.
Once all the spring rolls are made, heat oil in the wok to 375 F. Add 4 to 6 rolls and cook, agitating occasionally with a wire mesh spider, until golden brown and crisp, about 5 minutes. Drain on paper towels and keep warm. Repeat with remaining egg rolls. Serve immediately with vinegar or duck sauce for dipping.