Heat a wok or skillet over high heat.

Add canola oil and swirl to coat the pan.

Add garlic, ginger, and serrano chiles and cook until soft, about 2 minutes. Ensure aromatics do not burn.

Add ground pork and stir-fry until cooked through, about 3 to 5 minutes.

Add shredded cabbage, bamboo shoots, soy sauce, mushrooms, and Shaoxing wine. Cook until soft, about 3 minutes.

Add cornstarch slurry to thicken.

Season with salt and pepper to taste.

Transfer the filling mixture to a medium bowl and add scallions and bean threads to the cooled mixture.

Stir to blend.

Dampen a kitchen towel.

Place 5 egg roll wrappers on a work surface and cover the remainder with the cloth to prevent drying.

Place about 1/4 cup of the filling on the wrappers, just above the near corners.

Bring the corner nearest you up over the filling and roll halfway; brush the edges with the egg wash, then fold in the side corners and continue rolling to enclose the filling completely.

Roll as tightly as possible.

Cover with the cloth and allow the rolls to rest, seam side down.

Fill and roll the remaining wrappers, cover, and allow the rolls to rest at least 2 minutes.

Fill a fryer or heavy medium pot 1/3 full with oil and heat to 350 degrees over high heat.

Add the egg rolls 4 to 6 at a time and fry them until light golden, turning as needed, about 5 minutes.

Remove with a slotted spoon and drain on paper towels.

Fry again at 350 degrees just before serving for extra crispiness.

To Serve: Place a spoonful of Sweet and Sour Sauce in the middle of a serving plate.

Slice the rolls on the diagonal and arrange 3 of them around the sauce.

Drizzle the spicy mustard around the outside of the plate and serve.

For the Sweet and Sour Sauce: In a saucepan over medium high heat, add rice wine vinegar, soy sauce, Shaoxing wine, pineapple juice, brown sugar, and white sugar.

Bring to a boil and then reduce the heat to medium.

Add red chile flakes, pineapple, mango, peppers, and cornstarch, and let simmer for 2 minutes.

Serve hot.

For the Spicy Mustard: In a small bowl, whisk together the dry mustard, Dijon mustard, and sugar until a smooth paste is formed.