To PrepSoftened the shiitake mushrooms by soaking for about 10 mins. Keeping the water for later, remove the mushrooms, discard the stems and chop the caps finely.Soak eggplant in cold water 2-3 times and drain. This helps to remove bitterness.Heat water in a saucepan in medium-high to just before boiling. Add the tofu cubes and turn the heat to medium-low when the tofu begins to sway. Simmer for 2-3 mins and drain.Combine all sauce ingredients with the shiitake water and mix well.To CookIn a wok, heat the sesame oil along with the garlic, ginger, leeks, shiitake, eggplants and chilli bean paste. Stir-fry for 3 mins. Add the sauce mixture to the wok and bring to boil. Turn the heat to medium and add in the tofu. Stir gently without breaking the tofu, then summer for about 5 mins before turning off the heat.Sprinkle some sansho or Sichuan pepper and garnish with spring onions. Serve with rice.