Soak dried mushrooms in 1 cup of boiling water in a medium bowl for 15 minutes. Remove and discard the tough stems. Cut the caps into thin slices.
Heat a wok over high heat until smoking. Add 1 tablespoon of oil and swirl it around the wok. Add ground pork and stir-fry for 3-4 minutes or until no longer pink. Remove to a plate.
Add 1 tablespoon of oil, then stir-fry napa cabbage, bamboo shoots, and rehydrated shiitake mushrooms for 1 minute.
Add cooked pork, salt, soy sauce, and white pepper, and stir-fry for another minute. Turn off the heat, add sliced scallions, transfer to a bowl, and cool for 10 minutes.
Sweet Chili Sauce
Combine all the sauce ingredients in a saucepan over medium heat and cook until thickened.
Wrapping
In a small bowl, whisk egg with 1 tablespoon of water.
Place a spring roll wrapper on your work surface with the corner facing away from you. Add 3 tablespoons of filling 2 inches from the corner and sides. Roll from the nearest corner and fold in the sides when the bottom corner covers the filling. Roll tightly, dampen the edge with egg wash, and seal before reaching the end. Transfer to a baking sheet or plate, seam-side down. Repeat with remaining wrappers and filling.
Frying
Heat 1 inch of oil to 375°F. Fry 6-8 spring rolls at a time until golden brown, moving them back and forth and turning them for 4-5 minutes. Transfer to a wire rack to drain excess oil.
Notes
Storage: Refrigerate fried spring rolls in an airtight container for up to 3 days.Freezing: You can freeze uncooked spring rolls for up to 3 months. After wrapping them, put them on a tray with parchment paper, leaving space between them. Freeze for about 2 hours until they're semi-firm, then transfer them to a ziplock bag for long-term storage. To reheat, simply fry them for an extra minute or two. Since the filling is already cooked, it just needs to be reheated.