Heat oil till quite hot. Add pork with 1 teaspoon cornstarch. Fry until white. Remove and drain on paper towels. Heat 3 cups water to boiling. Dissolve remaining cornstach in small amount of water. Add vinegar, sugar, salt, pepper, bamboo shoots, wood ears, mushrooms and tofu to boiling water. When it returns to a boil, remove from heat. Add cornstarch mixture. While stirring, pour in beaten egg and sesame oil. Add pork. Season to taste.