You will need
Drain the mushrooms and slice very thinly
Slice the meat very thinly
Pour the stock into a saucepan and bring to the boil
Add the mushrooms and meat and simmer for 5 minutes
Meanwhile drain the tofu and pat dry. Cut into thin slices. Add to the pan with the vinegar and soy sauce. Heat gently
Crack the eggs into a bowl and add the chilli oil, to taste. Beat well. Pour into the hot soup in a thin, steady stream then stir vigourously with a fork until the eggs form threads.
Add salt to taste.
cooking for one or two