To prepare the tofu, in a pot, bring water to a boil and add a pinch of salt, then gently lower the tofu into the water and cook for 1 minute. Remove the tofu and set it aside.
To make the sauce, in a bowl, combine the soy sauce, Sichuan peppercorn powder, salt, white pepper, and sugar, then mix well.
To infuse the oil, in a pan over low heat, add the cooking oil and Sichuan peppercorns, and cook until fragrant. Then remove and discard the peppercorns.
To cook the pork, increase the heat to high, add the ground pork, and stir-fry until lightly browned. Remove and set aside.
To build the base, in the same pan over high heat, add the Pixian broad bean paste and stir-fry until the oil turns red and fragrant, then add the ginger, garlic, and white scallions and stir-fry briefly.
To braise, pour in the sauce and chicken stock and bring to a simmer, then gently slide in the tofu and return the pork. Let it cook for about 3 minutes.
To thicken, in a small bowl, mix the cornstarch with the water to form a slurry, stir again, then pour into the pan and gently mix until the sauce thickens.
To serve, garnish with the green scallions and serve immediately.