Heat the oil in a Dutch oven large enough to hold the final soup. Saute the onions and white parts of the green onions about 5 minutes. Add the mushrooms and cook another 5 minutes until liquid starts to release.

Add the ginger, garlic and hot sauce. Cook 1 minute.

Add the vinegar and tamari and stir in. Add the broth and bring to a boil. Reduce heat and simmer 10 minutes to mix flavours. Meanwhile shake the cornstarch and ⅓ cup of water in a small jar til well mixed and a small slurry is formed. Add slurry to the pot and simmer another 10 minutes til thickened, stirring occasionally.

Remove from heat and stir in the whisked egg. It will form stringy bits. Garnish with green onion bits and serve.