Start by filling a large pot with water and bringing it to a rolling boil. Add the shredded cabbage, grated carrots and chopped celery, blanching the vegetables about two minutes. To stop the cooking, immediately transfer them to an ice bath. Drain well and pat dry with a clean kitchen towel to remove any residual moisture — it’s important because this will help ensure you don’t end up with soggy egg rolls.

Transfer the drained vegetables to a large mixing bowl. Add the sliced scallions, salt, sugar, white pepper, and five-spice powder, if using. Drizzle in the sesame oil and your oil of choice for cooking. Add the roast pork and shrimp, if using. Be sure to mix until all ingredients are evenly distributed through the filling.

To assemble, place a spoonful of the filling in the center of an egg roll wrapper. Compress the filling lightly to shape, then roll the wrapper burrito-style, folding in the sides as you go. Brush the edges lightly with the beaten egg to seal. Repeat this until all the wrappers and filling are used, arranging the completed rolls on a lightly floured surface.

Heat enough oil in a deep pot to 325°F (160°C). Depending on the size of your pot, add a few egg rolls to the hot oil, but can’t overpopulate. Fry for about five minutes, turning occasionally to brown them evenly. Fry until each roll is crisp and golden.

Remove the egg rolls from the oil and let them rest for a moment before serving. Leftovers can be kept in bags that are safe for the freezer. To reheat, bake in a preheated oven at 350°F (175°C) until hot and crispy.