This is a vegetarian version of the Sichuan classic MaPo tofu. The flavor profile is hot and numbing which is known as Mala. Cut back on the chili powder if you don't like it so hot. The Sichuan chili bean paste is the key ingredient for the flavor and is also called Pixian Doubanjiang or Pixian Douban. Pixian is the area that is is from and the Doubanjiang or Douban is the paste. The paste is made from fermented fava beans, chili, flour and salt. It will be sold in bags or packs or in jars. The jar version contains oil. Both will keep for a long time in the fridge. Serve with rice.
For Chinese cooking we recommend preparing all the ingredients first as the cooking tends to go quite fast.
Put the Sichuan peppercorns in a dry pan on medium heat. Shake the man every now and then for a minute or two until the pepper corns smell fragrant. If they start to blacken you have cooked them too far. Take them of the heat and grind in a pestle and mortar or a coffee grinder that you only use for spices.
Cut the tofu in to large cubes, about 1 inch by 1 inch. Put in a bowl and pour boiling water over them and leave to seep for 10 minutes or put them in a sauce pan and very gently simmer for 5 to 10 minutes. This will firm the tofu up even more and stop it breaking apart in the final dish.
Slice the scallions, or baby leeks if using, on the diagonal in to thin slices.
Discard the tough Shiitake mushroom stems and slice up the caps. Fry in one tablespoon of oil. until they have lost their moisture and started to crisp up. remove for the pan for later.
Add two tablespoon of oil to the pan, fry the Sichuanese chili bean paste and chili powder for 30 seconds then add the chopped fermented black beans and garlic and fry for another 20 seconds
Add the stock to the flavored oil, mix then add the tofu and mushrooms. Stir gently so that you don't break up the tofu and simmer for 5 minutes.
Add the scallions and stir and cook for a minute. If using baby leeks cook for 2 minutes. Then give the cornstarch another stir and add to the pan. Stir to thicken the sauce and cook for one more minute.
Pour the cooked dish into a serving bowl and sprinkle with the ground roasted Sichuan peppercorns.