For each egg roll, place an egg roll skin on a flat surface with a corner pointing toward you. Spoon about 1/4 cup of the Pork Filling across and just below center or egg roll skin. Fold bottom corner over filling, tucking it under on the other side. Fold the side corners over filling, forming an envelope shape. Roll egg roll toward remaining corner. Moisten top corner with water; press firmly to seal.
Heat oil in electric deep-fryer according to manufacturers directions. Fry egg rolls, a few at a time, for 2 to 3 minutes or until golden brown. Remove with slotted spoon; drain on paper towels. Keep warm in 300 degree F oven while frying remaining egg rolls. Serve with sweet-and-sour sauce or hot mustard. Makes 8 egg rolls.
Prepare egg rolls as in Step 1. For frying, use heavy 3-quart saucepan filled with about 2 inches cooking oil. Attach a deep-fat frying thermometer to side of saucepan. Heat oil over medium heat to 365 degree F. Fry egg rolls as in Step 2. Serve as above.
Cook ground pork, ginger root, and garlic for 2 to 3 minutes or until meat is no longer pink; drain fat. Add bok choy or cabbage, water chestnuts, carrot, and onion. Stir-fry 2 minutes more. Combine soy sauce, cornstarch, sugar, and salt; add to skillet. Cook and stir for 1 minute; cool slightly.