GROUND PORK PREP: Combine ingredients for the ground pork and mix well in a medium bowl. Let rest for 15 minutes.
VEGETABLE PREP: Very thinly slice the soaked mushrooms, then finely chop them. Or food process them by pulsing a few times.
Heat a wok or large saute pan over medium-high heat. Add cooking oil, then add pork and stir-fry until no longer pink, about 3 minutes.
Reduce heat to medium and push the pork to the side of the pan. Add the vegetables - garlic, ginger, cabbage, carrots, mushrooms and stir-fry for about 2 minutes, just until vegetables are softened. Move to the side as much as you can, tilt pan so juices run to one side, and add the mung bean thread noodles. Cut them into pieces with poultry shears for easier handling, and stir-fry all ingredients another 2-3 minutes.
Add the remaining cooking ingredients except sesame oil and stir-fry for another minute. Add sesame oil, stir, then turn off heat. Remove from wok or pan using a slotted spoon and place ingredients in a shallow pan - you want to leave the juices in the pan. Allow filling to cool.
WRAPPING PREP: While waiting for the filling to cool, carefully separate thawed sheets of egg roll wrappers by peeling them, starting at one corner and working your way across. Stack them in a pile and keep covered with plastic wrap until ready to wrap.
WRAPPING: Have wrappers, beaten egg in a dish, a tablespoon, the cooled filling, and a baking pan or cookie sheet ready. Take one wrapper, and starting about 2 inches from one corner, scoop up a heaping tablespoon of filling and gently spread it diagonally at one end of the wrapper. Take the corner and fold it over the filling, tucking the corner in, and then fold over until you are at about the halfway point. Take both ends of the wrapper and fold them inwards (about 2 inches from each end) towards the center of the egg roll. Continue folding towards the corner. Just before you get to the corner, dab some egg wash along the corner edges, then finish rolling. Place on the pan.
Your egg roll should measure about 1-1/2 inches in diameter. Repeat wrapping process until all filling is used up.
FRYING: Heat oil in a deep pot or fryer to 350-360°F. Gently place 4-6 egg rolls into the fryer and fry, turning occasionally, until golden brown, about 1-1/2 minutes. Place on a wire rack to drain and cool.
Serve warm with your favorite sweet & sour dipping sauce.