Ginger Pork Pot Stickers

Make dumplings: In a large bowl, combine pork, broth, white parts of green onions, garlic, soy sauce, sesame oil, ginger, fish sauce if using, and egg. Stir ingredients together, using your hands or a wooden spoon, until fully combined. Line a small baking sheet with parchment paper and dust lightly with flour. Place 4 dumpling wrappers on your work surface, and keep remaining wrappers covered with a clean kitchen towel. Place a heaping teaspoon pork filling just below center on each wrapper. Wet the edge of wrapper with water and fold top half over bottom half and pinch border to seal. Alternatively, pleat dumplings by making small folds starting on one edge and ending on the other, pinching firmly to seal after each fold. Place on prepared baking sheet and continue stuffing and sealing dumplings until all pork mixture is used. Heat 1 tablespoon vegetable oil in a large skillet over medium heat. Add dumplings in an even layer, sealed side up. (Touching is OK!) Fry for 1 to 2 minutes, or until golden on the underside. Add 1/3 cup water to skillet, lower heat to medium-low, and cover with a tight-fitting lid. Let steam for 3 minutes, then adjust lid so it is ajar, allowing steam to escape. Cook until no water remains, about 3 minutes more. Use a spatula to transfer dumplings to serving plate, crisp side up. Repeat process until all dumplings are cooked. Make dipping sauce: Combine soy sauce, rice wine vinegar, and reserved green parts of green onions in a medium bowl and stir to combine.  Serve pot stickers with dipping sauce on the side.