Add the chicken broth, the reserved cup of mushroom liquid, soy sauce, vinegar, sugar, chile oil, chile paste (adding more according to desired level of heat), and pepper to the pot.
Add the pork, stirring to prevent the pork from sticking together (this is important!), the bamboo shoots, and mushrooms. Close the pot, and set to cook on high pressure for 6 minutes.
While the mixture cooks, prep the egg mixture in a separate bowl. Lightly beat two eggs.
When the cook cycle is complete, allow a ten-minute natural pressure release.
After ten minutes, finish the pressure release. Remove the lid.
Set the pot to saute on high (it needs to keep boiling).
Remove a cup of liquid, and add the cornstarch to it. Return the mixture to the pot and allow to thicken.
Mix well. If the soup is too thin, the spices won't be in suspension, and will sink to the bottom of each soup bowl, so thicken more if needed.
If using tofu, add it now and simmer for another minute.
Gently stir the soup to get it all rotating in one direction, then pour the egg mixture in a steady stream into the simmering soup, turn the pot off, and let sit for a few minutes.
Stir gently.
Add the sesame oil and green onions. If desired, both can be added to each bowl, or added by the diner. Just a few drops of sesame oil are often sufficient!