This dish is probably so far of the real deal that I might as well give it a different name. The reason is that I cant get all the ingredients in my local store and I want to keep it simple. So I just put whatever I think works and I have available. The only real important authentic ingredient are Sichuan peppercorns. But they can be stored for years so I just keep some in my cupboard.
I will typically not specify the amount of ingredients as it does not matter. Just be reasonable and don't waste food. Better put too much of something than to through the rest away.
Chop up some mushrooms and fry them. Add in the whites of some scallions, garlic, ginger and chilli. Then pour in some mashed black beans (I don't like using half cans so I just put a full can), a dash of rice wine and vinegar, a bit of sesame oil and most importantly a tsp of ground Sichuan peppercorns. Dilute with water until it is slightly runny. After a few minutes add tofu cubes and let them simmer a few minutes. Finally mix a tbs cornstarch with 2 tbs water and pour in. Add soy sauce to taste.
Serve with rice, chilli sauce and the green of the scallions.