Soak the mushrooms and gold needles in warm water for 30 minutes. Cut the pork into fine, match-sized strips. Mix the ingredients for the marinade and marinate the meat with them for 60 minutes, then stir the sesame oil into the mixture.
Strain the mushrooms and gold needles and gently squeeze out the water. Cut the mushrooms into very fine strips and cut the gold needles into pieces approx. 5 cm long. Cut the tofu crosswise into approx. 5 mm thick slices. Mix the potato flour with the water and have it ready. Put the clear broth in a 2 liter saucepan. Add mushrooms and gold needles. Season with salt, sugar and the soy sauces. Bring the broth to the boil and add the pork in small portions. Be careful not to stick the pieces together. Separate pieces that are stuck together.
Add the tofu pieces and as soon as the soup starts to boil again, pour in the potato flour mixture while stirring. Reduce heat supply. Whisk the egg with the salt and sunflower oil and pour a thin stream into the slowly rotating soup. Immediately remove the pot from the heat and let it mature for a minute with the lid on. Gently mix in the pepper and rice wine vinegar and add the sesame oil.
Garnish the soup with the celery leaves and the seedlings, serve very hot and consume with pleasure. Served with rice, it's a full meal.