For the Pork:
In a small bowl combine the cornstarch, soy sauce and white sugar. Add the strips of pork loin and stir to coat. Set aside.
In a 6 quart pot over medium heat, add the sesame oil, and then the pork. Stir to separate the pieces of meat and cook until browned on all sides, 3-5 minutes.
For the Soup:
Next add the 3 tablespoons soy sauce, white pepper, rice wine vinegar and sugar. Stir to combine, then add the chicken stock.
Bring to a boil, then add the mushrooms and the bamboo shoots. Stir to separate the ingredients and reduce the heat to simmer for 3-5 minutes, allowing the flavors to meld.
While the soup is simmering, combine the cornstarch and water in a small bowl and whisk into a slurry. Increase the heat to medium-low and slowly add the slurry, stirring as you go. Continue stirring and cooking over medium-low heat until the soup is thickened and then add the tofu. Adjust seasonings, if needed with salt to taste or more rice wine vinegar if you'd like more sour.
Return soup to a boil and slowly pour in the beaten egg. Immediately remove from heat and serve. Garnish with sliced scallions and Enoki mushrooms