In a mixing bowl soak dried mushrooms for 30 minutes in enough warm water to cover. Rinse well and squeeze to drain thoroughly. Chop finely, discarding stems. Set aside. Cut tofu into 1/4-inch cubes. In a bowl stir together the water, soy sauce, cornstarch, sugar, and sesame oil.
Pour the 1 tablespoon cooking oil into a large skillet. (Add more oil as necessary during cooking.) Preheat over medium-high heat. Stir-fry garlic in hot oil for 15 seconds. Add the regular cabbage (if using) and stir-fry for 1 minute. Add the carrots and stir-fry for 1 minute. Stir the soy mixture. Add to the skillet. Cook and stir until thickened and bubbly. Cook and stir 1 minute more. Stir in the mushrooms, tofu, and, if using, Chinese cabbage. Remove from skillet and cool.
In a wok or 3-quart saucepan heat 1-1/2 to 2 inches of cooking oil or shortening to 365 degree F.
Meanwhile, place an egg roll wrapper with a point toward you. Spoon about 1/4 cup of filling across and just below the center of the egg roll wrapper. Fold the bottom point of the egg roll wrapper over the filling. Then tuck it under the filling. Fold the side corners of the egg roll wrapper over the filling, forming an envelope shape. Roll the egg roll toward the remaining corner. Moisten the top point and press firmly to seal.
Fry egg rolls or wontons, a few at a time, in the hot oil for 1 to 2-1/2 minutes or until golden, turning once. Using a wire strainer or slotted spoon, remove food from oil. Drain on a wok rack or on paper towels. Keep warm in a 300 degree F oven while frying remaining food. Serve warm with Chinese Mustard Sauce or Chili Dipping Sauce. Makes 10 appetizer servings.