Slice mushroom, chop garlic, ginger, spring onion white, doubanjiang and fermented black beans.
Cut tofu into square cubes (around 2cms). Bring a large amount of water to a boil and then add a pinch of salt. Slide the tofu in and cook for 1 minute. Move out and drain.
Fry doubanjiang for 1 minute over slow fire until the oil turns red and then add garlic, scallion white, ginger and fermented black beans to cook for 30 seconds until aroma. Then fry mushrooms until soft.
Add water to the seasonings and bring to boil over high fire. Gently slide the tofu cubes. Add light soy sauce and sugar.Slow the heat after boiling and then simmer for 6-8 minutes. Drizzle some sesame oil.
Stir the water starch and then pour half of the mixture to the simmering pot. Wait for around 30 seconds and then pour the other half. You can slightly taste the tofu and add pinch of salt if not salty enough.
Transfer out when almost all the seasonings stick to tofu cubes. Sprinkle Szechuan peppercorn powder (to taste).