Cut the firm tofu into cubes and soak in slightly salted water for around 10 minutes. Transfer out and drain.
In a separate bowl, marinate minced pork with marinating sauce.
Drain the tofu. Heat up a saucepan over medium-high heat, add in the pork and stir-fry until fragrant and crispy. Add ginger, garlic, and Sichuan peppercorn and fry for 1 minute until aromatic (over slow fire).
Pour in oyster sauce.
Add the tofu cubes into the saucepan and pour in dark soy sauce (for coloring)as well. Stir-fry to combine all ingredients together.
Pour ¼ of water, reduce heat, and simmer for 5 to 6 minutes or until most of the liquid has evaporated. Sprinkle some chopped green onion and serve immediately.