In a wok or large skillet, heat 1 tablespoon of vegetable oil over medium-high heat.
Add the grated ginger and minced garlic, and sauté for about 30 seconds until fragrant.
Add the shredded cabbage, julienned carrots, chopped green onions, and bean sprouts. Stir-fry for 2-3 minutes until the vegetables are slightly softened.
If using, add the cooked and diced shrimp or ground pork to the vegetable mixture.
In a small bowl, mix together the soy sauce, oyster sauce, and sesame oil. Pour the sauce over the vegetable and protein mixture.
Stir-fry for another 2-3 minutes until everything is well combined and cooked through. Season with salt and pepper to taste. Remove from heat and let the filling cool.
Take an egg roll wrapper and place it in a diamond shape in front of you. Spoon a generous amount of the filling onto the center of the wrapper.
Fold the bottom corner of the wrapper over the filling. Roll it up slightly, then fold in the side corners and continue rolling tightly.
Dip your finger in the beaten egg and use it to seal the top corner of the wrapper, forming a seal.
Repeat the process with the remaining egg roll wrappers and filling.
In a deep pan or wok, heat vegetable oil for frying to around 350°F (175°C).Carefully place the egg rolls into the hot oil, a few at a time, and fry until golden brown and crispy. This should take about 3-4 minutes. Remove the egg rolls with a slotted spoon and drain them on a paper towel-lined plate.Serve the Egg Rolls hot with your favorite dipping sauce, such as sweet and sour sauce or soy sauce.